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345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
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90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
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012 3456789014567890123456789012
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1234
498
NEW CENTURY MATHS 7
Chapter 1
Start up
1 a
100
b
28
c
930
d
16
e
1000
f
7
g
81
h
18
i
1250
j
30
k
9
l
59
m
54
n
84
o
104
p
32
q
182
r
420
s
312
t
2800
u
3542
2 a
forty-five
b
one hundred and twenty
c
one hundred and thirty-eight
d
three thousand, six hundred and eighty
e
five thousand and one
f
forty-seven thousand, six hundred and thirteen
3 a
68
b
700
c
2004
d
899
e
10 492
Exercise 1-01
2 a
32
b
16
c
162
d
1246
e
1 120 000
4
(Answers may vary. Check with your teacher.)Advantage: you can write symbols anywhereDisadvantage: it is time consuming.
5
A million is a very big number and the man has his hands up in amazement.
1 a b c
d
e
f
3 a b
c
d
or 50 or 130
or 3558
or 21
Exercise 1-02
1
To make 3, they joined the words for 2 and 1.To make 4, they joined the words for 2 and 2.
2
To make 4, they used the word for 2 twice.To make 5, they used the words for 2 and 3To make 6, they used the word for 3 twice.
3 a
booleroo booleroo
b
guliba guliba
c
bularr guliba
d
booleroo booleroo
e
guliba
f
guliba
4
Answers may vary. Check with your teacher.
Exercise 1-03
1 a
54
b
18
c
105
d
203
3
Answers may vary. Check with your teacher.
Exercise 1-04
1 a
26
b
40
c
264
d
54
e
2159
f
1990
g
98
h
1507
2 a
CCCLXV
b
XXXVI
c
LXXIX
d
XCVII
e
MMDC
f
CCCXLIV
g
IM
h
MMMCDLXXIII
3
They are cumbersome to use, and they take too long to write.
4
Answers may vary. Check with your teacher.
Exercise 1-05
1 a
29
b
47
c
520
d
961
e
7080
2 a b c d
3
Answers may vary. Check with your teacher.
Exercise 1-06
1 a
9 has a value of 9 (or 9 units)0 means there are no tens6 has a value of 600 (or 6 hundreds)six hundred and nine
2 a b
c d
e f
Answers
17 NCM7 2ed SB ANS.fm Page 498 Friday, June 6, 2008 11:19 PM
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
499
ANSWERS
b
9 has a value of 9 (or 9 units)3 has a value of 30 (or 3 tens)0 means there are no hundreds1 has a value of 1000 (or 1 thousand)one thousand and thirty-nine
c
4 has a value of 4 (or 4 units)0 means there are no tens1 has a value of 100 (or 1 hundred)0 means there are no thousands7 has a value of 70 000 (or 7 ten thousands)seventy thousand, one hundred and four
d
0 means there are no units6 has a value of 60 (or 6 tens)8 has a value of 800 (or 8 hundreds)4 has a value of 4000 (or 4 thousands)0 means there are no ten thousands5 has a value of 500 000 (or 5 hundred thousandsfive hundred and four thousand, eight hundred and sixty
e
1 has a value of 1 (or 1 unit)7 has a value of 70 (or 7 tens)6 has a value of 600 (or 6 hundreds)4 has a value of 4000 (or 4 thousands)3 has a value of 30 000 (or 3 ten thousands)1 has a value of 100 000 (or 1 hundred thousands)9 has a value of 9 000 000 (or 9 millions)nine million, one hundred and thirty-four thousand, six hundred and seventy-one
f
0 means there are no units0 means there are no tens0 means there are no hundreds7 has a value of 7000 (or 7 thousands)3 has a value of 30 000 (or 3 ten thousands)8 has a value of 800 000 (or 8 hundred thousands)5 has a value of 5 000 000 (or 5 millions)five million, eight hundred and thirty-seven thousand
g
1 has a value of 1 (or 1 unit)0 means there are no tens0 means there are no hundreds4 has a value of 4000 (or 4 thousands)four thousand and one
h
9 has a value of 9 (or 9 units)8 has a value of 80 (or 8 tens)6 has a value of 600 (or 6 hundreds)5 has a value of 5000 (or 5 thousands)0 means there are no ten thousands2 has a value of 200 000 (or 2 hundred thousands)two hundred and five thousand, six hundred and eighty-nine
i
6 has a value of 6 (or 6 units)3 has a value of 30 (or 3 tens)0 means there are no hundreds
0 means there are no thousands0 means there are no ten thousands0 means there are no hundred thousands4 has a value of 4 000 000 (or 4 millions)3 has a value of 30 000 000 (or 3 ten millions)thirty-four million and thirty-six
2 a
8796
b
3 000 088
c
2385
d
6907
e
420 830
f
309 211
g
1 280 460
h
12 000 901
3
You can write bigger numbers using fewer symbols/numerals, it is faster to write, it is easier for calculations.
4
B
5
C
7 a
5 units
b
50 (or 5 tens)
c
500 (or 5 hundreds)
d
5 units
e
5000 (or 5 thousands)
f
50 000 000 (or 5 ten millions)
8 a
3 units
b
300 (or 3 hundreds)
c
30 000 (or 3 ten thousands)
d
30 (or 3 tens)
e
300 000 (or 3 hundred thousands)
f
3 000 000 (or 3 millions)
9 a
4000 (or 4 thousands)
b
4000 (or 4 thousands)
c
4 units
d
4 000 000 (or 4 millions)
e
4 units
f
400 000 (or 4 hundred thousands)
10 a
17, 321, 8000
b
17, 27, 63, 707
c
16, 246, 432, 3596, 5369, 6125
d
123, 132, 213, 231, 321
e
82, 145, 450, 1045
f
43, 243, 721, 722, 4372
g
300 806, 308 022, 380 211, 392 084
h
1 429 950, 3 006 853, 4 766 372, 4 856 231
11 a
10 times
b
100 times
c
1000 times
d
1000 times
Exercise 1-07
1 a
(5
×
10)
+
(6
×
1)
b
3
×
10
3
+
5
×
10
2
+
6
×
10
+
2
×
1
c
4
×
10
2
+
1
×
10
+
6
×
1
6
Ten thousands Thousands Hundreds Tens Units
a
4 8
b
3 8 2
c
2 7 5 1
d
3 0 2 0
e
1 5 3 6 4
f
4 4 0 4 0
17 NCM7 2ed SB ANS.fm Page 499 Friday, June 6, 2008 11:19 PM
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56789012 9012345678890123456789012345678 1234512345678901234567890123 45678901234
345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
500
NEW CENTURY MATHS 7
d
5
×
10
2
+
0
×
10
+
2
×
1
e
1
× 103 + 0 × 102 + 0 × 10 + 1 × 1f 1 × 104 + 0 × 103 + 2 × 102 + 5 × 10 + 3 × 1g 3 × 104 + 8 × 103 + 0 × 102 + 0 × 10 + 2 × 1h 5 × 104 + 9 × 103 + 6 × 102 + 4 × 10 + 4 × 1i 3 × 103 + 8 × 102 + 0 × 10 + 9 × 1j 1 × 105 + 2 × 104 + 0 × 103 + 4 × 102 +
3 × 10 + 5 × 12 a 524 b 6537 c 429
d 6473 e 82 343 f 3057g 76 001 h 10 999 i 344 220j 900 999
3 B4 Answers will vary. Check with your teacher.
Mental skills 1A2 a 1800 b 26 000 c 770 000
d 1000 e 315 000 f 1 000 000g 2940 h 47 500 i 240j 1600 k 300 l 210m 12 000 n 9900 o 1600p 3500 q 400 r 500s 180 000 t 3 600 000
Exercise 1-08
1 a + 3 4 b + 15 41
7 10 11 28 43 69
2 5 6 19 34 60
c + 11 9
8 19 17
5 16 14
2 a − 19 25 b − 54 78
7 12 18 37 17 41
12 7 13 26 28 52
c – 243 412
128 115 284
239 4 173
3 a × 11 9 b × 2 5
8 88 72 15 30 75
5 55 45 23 46 115
c × 12 20
10 120 200
17 204 340
4 a ÷ 36 84 b ÷ 32 64
4 9 21 8 4 8
3 12 28 4 8 16
Mental skills 1B2 a 20 b 60 c 450 d 30
e 190 f 26 g 53 h 720i 6 j 6 k 4 l 9m 70 n 30 o 22 p 8q 40 r 8 s 800 t 6
Exercise 1-091 a 12 b 21 c 43
d 37 e 32 f 6g 36 h 29 i 5
2 a 25 304 = 25 × 12 + 4
b 36 505 = 36 × 14 + 1
c 3 99 = 3 × 26 + 21
c ÷ 60 100
4 15 25
5 12 20
5 a + 10 20 b + 14 16
40 50 60 12 26 28
80 90 100 13 27 29
c + 8 11
22 30 33
6 14 17
6 a − 20 15 b − 17 24
12 8 3 9 8 15
9 11 6 13 4 11
c − 16 19
7 9 12
8 8 11
7 a × 5 4 b × 7 5
3 15 12 8 56 40
7 35 28 1 7 5
c × 10 6
9 90 54
4 40 24
8 a ÷ 24 12 b ÷ 48 32
4 6 3 8 6 4
3 8 4 2 24 16
c ÷ 72 30
3 24 10
6 12 5
13---,1
14------,
2126------,
17 NCM7 2ed SB ANS.fm Page 500 Friday, June 6, 2008 11:19 PM
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56789012 9012345678890123456789012345678 1234512345678901234567890123 45678901234
345678901234567845678901234567890123456789012
2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
501ANSWERS
d 48 917 = 48 × 19 + 5
e 28 958 = 28 × 34 + 6
f 31 869 = 31 × 28 + 1
g 22, 594 = 22 × 27h 6 79 = 6 × 13 + 1
i 20 815 = 20 × 40 + 15
3 11 lollies 4 26 cm
Exercise 1-101 a 96 b 26 c 12 d 5
e 42 f 2 g 91 h 9i 19 j 12 k 245 l 0
2 a 13 b 10 c 4 d 2e 30 f 19 g 39 h 1i 25 j 23 k 118 l 48
3 C4 a 11 b 30 c 100 d 17
e 171 f 121 g 12 h 43i 21 j 2 k 83 l 4m 3 n 3 o 122 p 37
5 a (5 − 2) × 4 = 12 b 3 + 8 − 7 = 4c (15 − 3) × 5 = 60 d 15 − 3 × 5 = 0e 8 + (4 − 3) × 2 = 10 f 8 + 4 − 3 × 2 = 6g (8 + 4 − 3) × 2 = 18 h 6 + 4 × 0 = 6i (6 + 4) × 0 = 0 j 100 ÷ (10 + 10) = 5k 100 ÷ 10 + 10 = 20
6 a 84 ÷ 3 + 9 × 15 − 11 = 152b 84 ÷ 3 + 9 × (15 − 11) = 64c 84 ÷ (3 + 9) × 15 − 11 = 94
7 a 8 + 9 − 7 + 2 = 12b 3 × 5 + 2 + 1 = 18c 6 × 8 − (3 + 4) = 41d 6 + 11 + 8 ÷ 2 = 21e 8 ÷ (4 − 2) + 6 = 10f 10 × 5 − 8 + 2 = 44g (7 + 9) ÷ (3 + 5) = 2h 9 ÷ (4 + 5) + 7 = 8i 10 ÷ 2 × (5 + 7) = 60
(Other solutions may exist.)
Exercise 1-111 + − × ÷
plus minus times divide
and subtract multiply share
increase decrease product quotient
total difference lots of
more than less
take away
519------,
317------,1
28------,
113------,
38---,
2 a 15 − 6 b 48 + 12 c 12 � 5d 5 ≠ 3 + 6 e 7 × 8 fg 36 ÷ 4 h 52 i 12 + 8j 13 − 6 k 3 + 13 l 39 ÷ 3m 25 − 8 n o 13 ≠ 3p 999 � 1000
3 a 12 b 40 c 36 d 72e 49 f 9 g 22 h 22i 110 j 91 k 4 l 106
4 D5 a T b F c F d F e T f T
g T h F i F j T k F l Tm F n F o T p T q F r F
6 a 7130 � 860 b 2001 � 2010c 352 140 � 4 082 716 d 2651 � 2561e 3602 � 3206 f 13 253 � 1353g 8079 � 8097 h 1432 � 1483
7 a 36, 41 b 2, 3c 2, 3, 7, 11, 36, 41 d 41e 2 f 36, 41g 8 h 3, 7, 8, 11, 36, 41
Power plus1 O = 2, N = 3, G = 9
4 Solutions include:
5 S = 9, E = 5, N = 6, D = 7, M = 1, O = 0, R = 8, Y = 2. Carlos asked for $10 652.
7 Check with your teacher.
Chapter 1 revision
2 a guliba b bularr guliba
2 R N E F I O U V
One solution = 0 5 6 2 4 9 8 7
Another solution = 0 3 2 1 6 9 8 5
3 N I F S X E Y R T O
0 1 2 3 4 5 6 7 8 9
E F H N O R S T U V
i 6 7 8 1 4 5 3 2 9 0
ii 5 8 6 7 9 2 4 3 0 1
iii 4 5 9 6 1 2 8 7 0 3
iv 2 3 9 6 1 4 8 7 0 5
6 A D E G H I P R S T
a 8 5 2 9 6 0 4 3 7 1
b 0 9 8 6 7 4 2 5 1 3
16
1253
1 a b
17 NCM7 2ed SB ANS.fm Page 501 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
502 NEW CENTURY MATHS 7
4 a XII b XLc CLXXIX d MMIV
6 a 612 b 943 c 5499d 6002 e 9 750 076
7 a 38, 21, 19, 16, 14b 101, 98, 89, 88, 36c 2635, 2534, 2533, 2356, 2300d 12 913, 12 391, 12 300, 11 990, 11 391
8 a 40 (or 4 tens) b 4 (or 4 units)c 400 (or 4 hundreds)d 40 000 (or 4 ten thousands)
9 a 1 × 10 + 9 × 1b 2 × 102 + 8 × 10 + 3 × 1c 6 × 102 + 6 × 10 + 5 × 1d 4 × 104 + 2 × 103 + 8 × 102 + 9 × 10 + 1 × 1
10 a 94 b 208 c 22 d 39e 2559 f 234 g 615 h 396i 9 j 36 k 125 l 350
11 a 24, 384 = 24 × 16 b 48, 912 = 48 × 19
c 46 784 = 46 × 17 × 2
d 38 877 = 38 × 23 + 312 a 1 b 21 c 25 d15
e 2400 f 1400 g 11 h 26i 8 j 10 k 35 l 1 969 999
13 a 13 b 9 c 93d 21 e 27 f 190
14 a 7 + 3 − 1 = 9 b 10 ÷ (5 ÷ 5) = 10c 8 + 3 − 6 ÷ 2 = 8 d 28 ÷ 4 × 7 = 49e 6 × 4 ÷ 3 × 5 = 40f (19 + 1) ÷ 5 − (3 + 1) = 0
15 a T b T c T d T e T f T
Chapter 2Start up
1 a 20° b 25° c 15° d 20°e 40° f 80° g 60° h 57°i 70° j 94° k 28° l 81°
2 I and J3 A and H, B and I4 a E and F b D and E c C and E
d B and E e F and H f D and Jg A and I h A and J
5 Teacher to check.6 a acute b obtuse c obtuse
d acute e reflex f reflex
3 a b
5 a b
217------,
323------,
g acute h obtuse i reflexj obtuse k reflex l acutem acute n reflex o obtuse
Exercise 2-011 a ∠QPK, ∠P or ∠KPQ
b ∠OCR, ∠C or ∠RCOc ∠GVE, ∠V or ∠EVGd ∠TAG, ∠A or ∠GATe ∠PQD, ∠Q or ∠DQPf ∠RDC, ∠D or ∠CDR
2 C3 a ∠CAD or ∠DAC b ∠PMQ or ∠QMP
c ∠TQR or ∠RQT d ∠WXY or ∠YXWe ∠AED or ∠DEA f ∠FGE or ∠EGF
4 The following are examples, the sizes of the angles will differ.
5 a ∠NAY, ∠AYN or ∠AYC, ∠ANY or ∠ANC, ∠AND, ∠AYD, ∠NCD, ∠NDY, ∠NCY, ∠DNC or ∠DNY, ∠DCY, ∠CDY, ∠NYD or ∠CYD, ∠NDC (Remember that ∠NAY and ∠YAN are two ways of naming the same angle.)
b A straight angle.6 a ∠DBC or ∠CBD ∠ADB or ∠BDA
b ∠PSR or ∠RSP ∠PRQ or ∠QRPc ∠MRQ or ∠QRM ∠RNP or ∠PNRd ∠EIF or ∠FIE ∠FGI or ∠IGF e ∠DCF or ∠FCD ∠GBC or ∠CBGf ∠WXY or ∠YXW ∠YWZ or ∠ZWY
7 a ∠ADB and ∠CDB, or ∠CBD and ∠DBAb ∠SRP and ∠QRP, or ∠SPR and ∠QPRc ∠QMR and ∠NMR, or ∠RNP and ∠MNR,
or ∠NPR and ∠QPR, or ∠RQP and ∠RQM, or ∠MRQ and ∠QRP, or ∠QRP and ∠PRN, or ∠PRN and ∠NRM, or ∠NRM and ∠MRQ
d ∠EIF and ∠FIG, or ∠FIG and ∠GIH, or ∠HGI and ∠IGF, or ∠GFI and ∠IFE
e ∠ECD and ∠DCF, or ∠DCF and ∠FCB, or ∠FCB and ∠BCE, or ∠BCE and ∠ECD, or ∠GBC and ∠CBH, or ∠CBH and ∠HBA, or ∠HBA and ∠ABG, or ∠ABG and ∠GBC
f ∠XWY and ∠YWZ, or ∠XYW and ∠WYZ
a b
c d
O
P
T
TA
FA
FE
H
xxxxxx
17 NCM7 2ed SB ANS.fm Page 502 Friday, June 6, 2008 11:19 PM
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56789012 9012345678890123456789012345678 1234512345678901234567890123 45678901234
345678901234567845678901234567890123456789012
2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
503ANSWERS
Exercise 2-021 a 64° b 133° c 85° d 87°
e 129° f 175° g 157° h 112°2 a ∠AOB = 38° b ∠PDQ = 162°
c ∠XPY = 84° d ∠MAN = 121°e ∠TQS = 175° f ∠XYZ = 38°g ∠LMN = 82° h ∠GFD = 121°i ∠ADM = 162° j ∠BPZ = 47°k ∠ABC = 122° l ∠EFG = 38°
3 a ∠ABC = 213° b ∠XYZ = 300°c ∠LMN = 248° d ∠GHK = 330°
4 B5 a = 153° = 27°
b = 45° = 88° c = 67° = 119° d = 45° = 45° e = 114° = 78° f = 84° = 118°
Exercise 2-03
xxxxxx
a b1
c d
35° 115°
150°
40°
e f
g h
15° 170°
117°
200°
a b2
c d
e f
65°
145°
32°45°
D
E
R
B G
H
T
R G
C
A B
110°S
Q
A
265°N
H
M
Exercise 2-041 Teacher to check.2 a acute b obtuse c reflex
d reflex e acute f straightg obtuse h obtuse i revolutionj acute k reflex l obtusem acute n reflex o rightp reflex q obtuse r acute
3 D, A, H, F, C, B, G, E4 a obtuse
b looks acute but is actually a right anglec reflex d acute
5 D
Exercise 2-051 a ∠ABD = 26°, ∠CBD = 64°
∠ABD + ∠CBD = 90°b ∠XYZ = 44°, ∠XZY = 46°
∠XYZ + ∠XZY = 90°2 Teacher to check.3 a 60° b 20° c 65°
d 52° e 1° f 23°g 48° h 24° i 79°j 16° k 89° l 78°
4 a ∠ABD = 53°, ∠CBD = 127°∠ABD + ∠CBD = 180°
b ∠PQR = 110°, ∠SRQ = 70°∠PQR + ∠SRQ = 180°
5 Teacher to check.6 a 162° b 30° c 145°
d 55° e 118° f 93°g 69° h 7° i 126°j 48° k 172° l 89°
7 a 360°b i ∠ADB = 135°, ∠ADC = 135°,
∠BDC = 90°∠ADB + ∠ADC + ∠BDC = 360°
ii ∠AEB = 107°, ∠BEC = 90°, ∠CED = 76°, ∠DEA = 87°∠AEB + ∠BEC + ∠CED + ∠DEA = 360°
8 Teacher to check.
i
g h
28°L
Y
KL
MN
180°
K L
Y
90°
17 NCM7 2ed SB ANS.fm Page 503 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
504 NEW CENTURY MATHS 7
9 a m = 50 b q = 120 c x = 211d y = 145 e a = 98 f d = 151g w = 90 h f = 57 i n = 110j k = 208 k t = 180 l h = 57
10 D
Exercise 2-061 a c° b u° c a°
d f ° e i° f p°2 a a = 70 b m = 110
c k = 85 d m = 90e x = 135 f f = 25g w = 133 h n = 29i q = 62 j t = 163k h = 20, g = 160l q = 90, r = 90, s = 90
Exercise 2-071 a 48° b 53°2 a ∠MDQ b ∠NDP
c ∠QDN, ∠MDPd ∠MDQ and ∠QDP, ∠QDP and ∠PDN,
∠PDN and ∠NDM, ∠NDM and ∠MDQ3 A4 a ∠PQR and ∠RQS b ∠PQR and ∠RQS
c They add to 90°.5 a a = 60, supplementary angles
b a = 20, complementary anglesc y = 100, vertically opposite anglesd m = 135, supplementary anglese p = 120, angles at a pointf a = 120, angles at a pointg m = 71, complementary anglesh x = 41, vertically opposite anglesi f = 165, supplementary anglesj h = 170, vertically opposite anglesk a = 45, complementary anglesl t = 90, supplementary anglesm a = 32, vertically opposite angles;
b = 148, supplementary anglesn y = 53, angles at a pointo d = 135, angles at a pointp x = 70, complementary angles;
y = 90, supplementary anglesq e = 68, supplementary angles;
f = 112, supplementary anglesr j = 132, supplementary angles;
k = 48, supplementary angles;l = 132, supplementary angles
s x = 62, supplementary angles;y = 105, supplementary angles
t p =60, angles at a pointu e =60, supplementary angles
Exercise 2-081 AB, AC, AD, BC, BD, CD2 a FC and DA
b BG and CFc GB and HE, FC and HE, GB and DA,
FC and DA3 a FC ⊥ DA b BG || CF4 Answers should resemble these:
5 a ∠AEC and ∠BEC, ∠CEB and ∠DEB, ∠DEB and ∠DEA, ∠DEA and ∠AEC
b ∠AED and ∠BEC, ∠BED and ∠AECc ∠AEC and ∠BEC, ∠CEB and ∠DEB, ∠
BED and ∠DEA, ∠DEA and ∠AEC6 D 7 C8 Teacher to check.
Mental skills 22 a 117 b 740 c 138 d 140
e 174 f 100 g 436 h 109
Exercise 2-091 a g° b d° c d°
3 A4 Pairs of alternate angles are marked in the
same way.
a b
c d
CA
B
D
E
F G
P
Q L
K
Y
Z
M
J
a b2
c
a b
c
17 NCM7 2ed SB ANS.fm Page 504 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012
2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
505ANSWERS
5 a m = 110 b a = 50c n = 80 d b = 122e h = 20 f m = 50, n = 130, p = 50g a = 140, b = 40 h a = 130, b = 130i a = 136, b = 136, c = 44
Exercise 2-101 a f ° b c° c c°
3 Pairs of corresponding angles are marked inthe same way.
4 B5 a a = 120 b y = 28
c m = 63 d c = 108e t = 74 f a = 50, b = 60g m = 110, n = 70 h x = 105, y = 105i a = 40, c = 40, d = 140, y = 140
6 a = 75, b = 105, c = 75, d = 105, e = 75, f = 105,g = 75
Exercise 2-111 a d° b d° c c°
a b2
c
a b
c
a b2
c
4 A5 a a = 130 b m = 90
c b = 105 d d = 68e m = 112 f a = 82, b = 98g f = 50, g = 130 h j = 125, k = 125i a = 51, b = 129, c = 51
Exercise 2-121 a ∠WXQ b ∠XWP
c ∠WXS d ∠AWV or ∠XWPe ∠XWA f ∠XWP
2 a 65° b 71° c 105°d 120° e 110° f 132°g 28° h 72° i 95°j 93° k 81° l 30°m 128° n 114° o 109°
3 a a = 113, b = 113b j = 133, k = 133, l = 133c m = 52, n = 52, p = 128d y = 42, z = 42 e l = 95, m = 85f b = 45, c = 30 g p = 105, q = 105h k = 85, m = 85 i p = 63, w = 117j k = 50 k x = 118, y = 55l a = 72, b = 108m m = 97, n = 83, p = 83n g = 132o a = 153, b = 153, c = 27
4 C
Exercise 2-131 a ∠BEF and ∠CFE
AB || CD, alternate angles are equalb ∠AGH and ∠GHD
AB || CD, alternate angles are equalc ∠BEF and ∠EFC
AB is not parallel to CD, alternate angles are not equal
a3
or
b
or
c
or
17 NCM7 2ed SB ANS.fm Page 505 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
506 NEW CENTURY MATHS 7
2 a ∠GEB and ∠DFEAB is not parallel to CD, corresponding angles are not equal
b ∠AEF and ∠CFGAB || CD, corresponding angles are equal
c ∠CEF and ∠AFGAB is not parallel to CD, corresponding angles are not equal
3 a ∠AEF and ∠EFCAB || CD, co-interior angles add to 180°
b ∠BEF and ∠EFDAB is not parallel to CD, co-interior angles do not add to 180°.
c ∠AEF and ∠EFCAB || CD, co-interior angles add to 180°
4 a MN || PQ, co-interior angles add to 180°b PQ || MN, corresponding angles are equalc MN || PQ, alternate angles are equal,
corresponding angles are equald PQ is not parallel to MN, corresponding
angles are not equal, ∠PCB = 115° and ∠MAD = 120°
e MN is not parallel to PQ, alternate angles are not equal
f MN || PQ, co-interior angles add to 180°5 B
Power plus1 Teacher to check.2 a Teacher to check. b 180°
c Teacher to check. d 360°3 a 360° b 15°
c 120° d 2.5°4 a left b front
c behind d front5 a m = 51, vertically opposite, corresponding
anglesb x = 62, alternate angles; y = 62, alternate
anglesc a = 55, alternate, co-interiord m = 58, alternate, straight angle, or
co-interiore y = 75, teacher to check (corresponding)f k = 65, straight angle, angle sum of a
triangle; c = 35, alternate anglesg x = 85, alternate anglesh m = 255, teacher to check (corresponding
angles)i k = 105, teacher to check (corresponding,
co-interior, and vertically opposite)
Chapter 2 revision1 Teacher to check.2 Teacher to check.
4 a ∠WHI or ∠IHW, acute angleb ∠DAR or ∠RAD, obtuse anglec ∠GLU or ∠ULG, acute angled ∠PVR or ∠RVP, acute anglee ∠NPE or ∠EPN, right anglef ∠SAM or ∠MAS, obtuse angleg ∠MTV or ∠VTM, straight angleh ∠XYZ or ∠ZYX, reflex anglei ∠MPQ or ∠QPM, reflex angle
5 a i 55° ii 12° iii 86°b i 135° ii 80° iii 2°c i a = 220 ii m = 65 iii y = 325
6 a a = 100 b m = 44c a = 95, b = 85
7 a m = 62 b k = 133c x = 58, y = 122 d p = 145e x = 42 f f = 70g t = 83 h p = 155, q = 155, r = 25i x = 30
8 a AB and GHb EF and GH, EF and ABc AB and CD, AD and EF, GH and CD,
GH and EF9 a i ii
b i a = 38 ii b = 120iii a = 126, b = 126
a b3
c d
G
U J84°
A
Q R117°
41° OP
T
D G
E
150°
e f
g h
S A
R
96°
210°XD
W
195°M NB
270°D
O
L
300°
M
A
P
i
17 NCM7 2ed SB ANS.fm Page 506 Friday, June 6, 2008 11:19 PM
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
507ANSWERS
10 a i ii
b i a = 112 ii p = 117iii p = 150, n = 30
11 a i ii
b i k = 108 ii x = 68iii x = 98, y = 98
12 a alternate b co-interiorc corresponding d correspondinge alternate f corresponding
13 a a = 115 b m = 35 c k = 115d d = 125 e x = 50 f q = 62g x = 37, y = 37h m = 62, p = 118, z = 118 i a = 112, d = 68, t = 112
14 a x = 50, y = 50 b x = 26, m = 64c a = 72, c = 70, z = 38d a = 38, c = 142e x = 35, y = 88, z = 92
15 Teacher to check.16 a AB || CD, co-interior angles add to 180°
b AB is not parallel to CD, alternate angles are not equal
c AB || CD, corresponding angles are equal
Chapter 3Start up
1 2, 4, 6, 8, 10, 12, 14, 16, 18, 202 Even: 2002, 134, 2, 748, 90 704 006, 2074,
1 000 000, 1256Odd: 17, 371, 60 023, 691, 1, 95, 13, 99 999
3 1, 2, 3, 64 1, 2, 3, 4, 6, 8, 12, 245 2, 4, 6, 12, 18, 366 1, 3, 5, 9, 15, 457 The last digit is even.8 The last digit is odd.9 a 14, 16, 18 b 36, 39, 42
c 107, 109, 111 d 33, 31, 29e 29, 24, 19 f 31, 39, 47
10 64 11 312 Any of the following pairs: 1 and 48, 2 and 24,
3 and 16, 4 and 12, 6 and 8.
Exercise 3-011 a They form a triangular pattern.
b 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91c 1 + 2 + 3 + 4 + 5 = 15
1 + 2 + 3 + 4 + 5 + 6 = 211 + 2 + 3 + 4 + 5 + 6 + 7 = 281 + 2 + 3 + 4 + 5 + 6 + 7 + 8 = 36
d By adding the next whole number to the sum of the previous whole numbers each time.
e 50502 a The numbers each form a square array.
b 1, 4, 9, 16, 25, 36, 49, 64, 81, 100c 1 + 3 + 5 + 7 + 9 = 25
1 + 3 + 5 + 7 + 9 + 11 = 361 + 3 + 5 + 7 + 9 + 11 + 13 = 491 + 3 + 5 + 7 + 9 + 11+ 13 + 15 = 64
d By adding consecutive odd numbers together, starting with 1 and adding the next odd number to the total for each new term.
e 50 × 50 = 2500f i 1 + 2 + 3 + 4 + 3 + 2 + 1 = 42
1 + 2 + 3 + 4 + 5 + 4 + 3 + 2 + 1 = 52 1 + 2 + 3 + 4 + 5 + 6 + 5 + 4 + 3 + 2 + 1 = 62 1 + 2 + 3 + 4 + 5 + 6 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 72
ii 52 = 42 + (4 + 5)62 = 52 + (5 + 6)72 = 62 + (6 + 7)82 = 72 + (7 + 8)
g 4 = 1 + 3 9 = 3 + 616 = 6 + 10 25 = 10 + 1536 = 15 + 21 49 = 21 + 2864 = 28 + 36 81 = 36 + 45
100 = 45 + 55h 1, 36
3 a By starting with 1, 1, then adding the previous two numbers each time.
b 5 + 8 = 138 + 13 = 21
13 + 21 = 3421 + 34 = 5534 + 55 = 89
c 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597, 2584, 4181, 6765
i 2, 8, 34, 144, 610, 2584 (Each number divides evenly by 2)
ii 3, 21, 144, 987, 6765 (Each number divides evenly by 3)
iii 5, 55, 610, 6765(Each number divides evenly by 5)
d i 1, 3, 21, 55 ii 1
17 NCM7 2ed SB ANS.fm Page 507 Friday, June 6, 2008 11:19 PM
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8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
508 NEW CENTURY MATHS 7
e In the double spirals of a daisy wheel, the bumps on pineapples, and the leaves of many trees.
b Add the numbers to the immediate left and immediate right in the row above.
c 1, 2, 4, 8, 16, … They are the powers of 2.d Use the diagonal 1, 3, 6, 10, 15, 21, …
5 a 373, 656, 22, 191, 797b 1001, 1111, 1221, 1331, 1441, 1551, 1661,
1771, 1881, 1991c i one step ii two steps
iii one step iv two stepsv two steps vi four steps
vii five steps viii two stepsix one step
d Teacher to check.
Exercise 3-02
2 C3 a 15, or 30, or 45, or 60, or 75, or 90
b 20, 40, 60, 80c 42, 84d 12, 24, 36, 48, 60, 72, 84, 96
4 Teacher to check.
1 Number 2 3 4 5 6 7 8 9 10
252 ✔ ✔ ✔ ✔ ✔ ✔
600 ✔ ✔ ✔ ✔ ✔ ✔ ✔
88 ✔ ✔ ✔
121
6215 ✔
3720 ✔ ✔ ✔ ✔ ✔ ✔ ✔
747 ✔ ✔
4753 ✔
110 001 ✔
40 436 ✔ ✔
840 ✔ ✔ ✔ ✔ ✔ ✔ ✔ ✔
75 ✔ ✔
2 000 646 ✔ ✔ ✔ ✔
20 106 ✔ ✔ ✔ ✔
7434 ✔ ✔ ✔ ✔ ✔
601 295 ✔
4 a
11045120196
1 7 21 35 21 7 1
1 10 45 120 196
1936841 9 36 84 112
18281 8 28 56 56
Exercise 3-031 a Yes b Yes c No
d Yes e No f Yesg Yes h Yes i Noj Yes
2 a 1, 2, 4, 8, 16b 1, 3, 7, 21c 1, 2, 3, 4, 6, 8, 12, 24d 1, 2, 3, 4, 6, 9, 12, 18, 36e 1, 5, 7, 35f 1, 2, 3, 4, 6, 8, 12, 16, 24, 48g 1, 2, 4, 13, 26, 52h 1, 2, 4, 5, 8, 10, 16, 20, 40, 80i 1, 2, 4, 7, 8, 14, 16, 28, 56, 112j 1, 2, 3, 4, 6, 8, 9, 12, 16, 18, 24, 36, 48, 72,
144k 1, 2, 4, 7, 14, 28l 1, 2, 4, 5, 10, 20, 25, 50, 100m 1, 3, 5, 9, 15, 45n 1, 2, 4, 5, 8, 10, 20, 25, 40, 50, 100, 200o 1, 3, 11, 33, 121, 363
3 C4 a 1, 2 b 1, 3
c 1, 2 d 1, 2, 4e 1, 2, 5, 10, 25, 50 f 1, 23g 1, 5 h 1, 2, 4i 1, 2, 5, 10 j 1, 2, 3, 6k 1, 2, 3, 5, 6, 10, 15, 30l 1, 13 m 1, 3, 5, 15n 1, 3 o 1p 1, 2, 5, 7, 10, 14, 35, 70
5 a 1, 2 b 1, 2, 5, 10c 1, 11 d 1, 2, 3, 4, 6, 12e 1, 3 f 1, 2, 4, 8g 1, 2, 7, 14 h 1, 3, 5, 15i 1, 2, 5, 10
6 a 12 b 11 c 12 d 3e 3 f 16 g 4 h 2i 50 j 6 k 24 l 5m 7 n 9 o 25
7 False. The number 1 has only one factor, itself.
8 a 2 b 10 c 11d 12 e 3 f 8g 14 h 15 i 10
Mental skills 32 a 88 b 167 c 314
d 85 e 129 f 121g $11.60 h $6.75 i $4.70j $30.05 k $7.10 l $32.90
17 NCM7 2ed SB ANS.fm Page 508 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012
2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
509ANSWERS
Exercise 3-041 e They are all prime numbers.2 Primes: 17, 41, 59, 71, 101
Composites: 10, 27, 33, 62, 77, 129, 472, 999, 2064, 967 504
3 14 a 37, 41, 43, 47
b 66, 68, 69, 70, 72, 74, 75, 76, 77, 78c 2, 3, 5, 7, 11, 13, 17, 19d 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46
5 B6 Teacher to check.
Exercise 3-051 (Different factor trees are possible.)
a b
c d
e f
g h
i j
8 = 2 × 2 × 2
8
42
2 2 2
×
××63 = 7 × 3 × 3
63
97
7 3 3
×
××
45 = 5 × 3 × 3
45
95
5 3 3
×
××
36 = 2 × 2 × 3 × 3
36
182
2 9
×
×
2 3× 3×2 ×
2×
51 = 3 × 17
51
173 ×49 = 7 × 7
49
77 ×
90 = 5 × 2 × 3 × 3
90
185
5 9
×
×
2 3× 3×5 ×
2×
27 = 3 × 3 × 3
27
93
3 3 3
×
××
130 = 5 × 2 × 13
130
265
5 2 13
×
××
200 = 2 × 2 × 2 × 5 × 5
200
1002
2 10
×
×
2 2× 5×2 ×
10×
× 5
k l
m
n
o
2 D3 a 162 b 60 c 225
d 980 e 90 f 364 a b
c d
e f
275 = 5 × 5 × 11
275
555
5 5 11
×
××
342 = 2 × 3 × 3 × 19
342
1143
3 57
×
×
2 3× 19×3 ×
2×
1250 = 2 × 5 × 5 × 5 × 5
1250
2505
5 5 50
×
× ×
5 5 5×× 10×
5 × 5 5× 5 2××
1020 = 2 × 2 × 3 × 5 × 17
1020
2045
5 2 102
×
× ×
5 2 3×× 34×
5 × 2 3× 2 17××
837 = 3 × 3 × 3 × 31
837
939
3 3 31
×
××× 3
18 = 2 × 32
18
92
2 3 3
×
××
20 = 22 × 5
20
45
5 2 2
×
××
45 = 32 × 5
45
95
5 3 3
×
××
72 = 23 × 32
72
362
2 6
×
×
2 2× 3×2
6×
3× ×
98 = 2 × 72
98
492
2 7 7
×
××
196 = 22 × 72
196
494
2 7 7
×
×× 2 ×
17 NCM7 2ed SB ANS.fm Page 509 Friday, June 6, 2008 11:19 PM
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8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
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012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
510 NEW CENTURY MATHS 7
g h
i
j
Exercise 3-06
2 1 and 643 a 7056 b 15 129
c 576 d 17644 a 121 b 3375 c 10 000
d 300 763 e 0.01 f 42.8755 a 3 b 4 c 9 d 11
e 5 f 2 g 6 h 10
6 a 2 b 5 c 7 d 10 e 9 f 30
7 B 8 D 9 8 and 910 a 7.1 b 11.9 c 31.6
d 4.1 e 9.9 f 4.9
11 a = = 2 × 11= 22
1 Number 1 2 3 4 5 6
Number squared
1 4 9 16 25 36
Number cubed
1 8 27 64 125 216
Number 7 8 9 10 11 12
Number squared
49 64 81 100 121 144
Number cubed
343 512 729 1000 1331 1728
32 = 25
32
162
2 4
×
×
2 2× 2×2
4×
2× ×135 = 5 × 33
135
275
5 9
×
×
3 3 3×5
3×
× ×
200 = 23 × 52
200
1002
2 4
×
×
5 2× 2×2
25×
5× ×
900 = 22 × 32 × 52
900
1009
3 25
×
×
2 5× 5×3
4×
2× ×
× 3
×3
484
1214
2 11 11
×
××× 2
484 2 2× 11× 11×
b
= = 2 × 3 × 7= 42
c = = 5 × 5= 25
d
= = 2 × 3 × 5= 30
e
= = 2 × 2 × 7= 28
f
= = 2 × 2 × 2 × 2= 16
g = = 2 × 7= 14
1764
4414
2 2 147
×
× ×
2 2 3×× 49×
2 × 2 3× 7 7×× 3 ×
3×
× 3
1764 2 2 3 3 7 7×××××
625
1255
5 25
×
5 5×5
×
×
× 5
5 ×
625 5 5× 5× 5×
900
1009
3 4
×
×
5 2× 2×3
25×
5× ×
× 3
3 ×
900 2 2× 3× 3× 5× 5×
784
1964
2 49
×
×
2 7× 7×2
4×
2× ×
× 2
2 ×
784 2 2× 2× 2× 7× 7×
256
644
2 2 16
×
× ×
2 2 2×× 4×
2 × 2 2× 2 2××
4×
4×2
2 ×2
×
×2×
256 2 2× 2× 2× 2× 2× 2× 2×
196
494
2 7 7
×
××× 2
196 2 2 7 7×××
17 NCM7 2ed SB ANS.fm Page 510 Friday, June 6, 2008 11:19 PM
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
511ANSWERS
h
= = 2 × 2 × 5= 20
i
= = 2 × 2 × 2 × 7= 56
12 a 22 b 14 c 15d 40 e 17 f 21
Power plus1 a 22 b 128 c 500
d 47 e 120 f 302 a 23, 32, 52, 25, 53, 35
b 52, 82, 63, 35, 44, 73 c 114, 34, 27, 54, 1002
3 a 1, 121, 12 321, 1234 321b i 123 454 321
ii 1 234 567 654 321iii 12 345 678 987 654 321iv 1 234 567.876 543 21
4 a 2 + 3 + 4 = 1 + 8 = (1)3 + 23 5 + 6 + 7 + 8 + 9 = 8 + 27 = (2)3 + (3)3 10 + 11 + 12 + 13 + 14 + 15 + 16 = 27 + 64 = (3)3 + (4)3
b 17 + 18 + 19 + 20 + 21 + 22 + 23 + 24 + 25= 64 + 125 = (4)3 + (5)3 26 + 27 + 28 + 29 + 30 + 31 + 32 + 33 + 34+ 35 + 36 = 125 + 216 = (5)3 + (6)3
c i Number of terms from 50 to 64 is 15.7 + 8 = 15Sum = (7)3 + (8)3 = 855
ii Number of terms from 82 to 100 is 19.9 + 10 = 19Sum = (9)3 + (10)3 = 1729
iii Number of terms from 290 to 324 is 35. 17 + 18 = 35Sum = (17)3 + (18)3 = 10 745
400
1004
2 25
×
×
2 5× 5×2
4×
2× ×
× 2
2 ×
400 2 2× 2× 2× 5× 5×
3136
15682
2 784
×
×
2 2× 196×
2 × 2 2× 4 49×
2×
4×
×2×
2 × 2 2× 7 7××2× 2 2× ×
3136 2 2× 2× 2× 2× 2× 7× 7×
iv Number of terms from 577 to 625 is 49. 24 + 25 = 49Sum = (24)3 + (25)3 = 29 449
5 a 50 b 90 c 100d 1000 e 1100 f 10 000g 800 h 420 i 100000
6 a 20 b 70 c 100d 400 e 1000 f 30
7 a 6 b 60 c 42 d 408 a 2 b 20 c 42
d 6 e 200 f 639 a 9 b 9 c 200
d 8 e 75 f 210 3 and 5, 5 and 7, 11 and 13, 17 and 19, 29 and
31, 41 and 43, 59 and 61, 71 and 73
Chapter 3 revision1 a 9, 11, 13 b 10, 12, 14 c 15, 21, 28
d 25, 36, 49 e 13, 21, 34 f 40, 35, 302 a 1, 4, 9, 16, … (d) b 1, 3, 6, 10, … (c)
c 1, 1, 2, 3, 5, 8, … (e)3 a 15 b 34 c 2112
d 31 e 4, 6, 8, 9, 10 f 494
5 a 3, 9 b 3 c 2, 3, 4, 6d 2, 5 e 2, 3, 6, 7
6 a 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60b 1, 2, 3, 6, 7, 14, 21, 42
7 a 1, 2, 3, 6 b 4 c 128 2, 13, 17, 19, 29, 31, 37, 67, 73, 83, 899 a b
c d
e f
1 5 10 10 5 1
17211 7 21 35 35
161 6 15 20 15
24 = 2 × 2 × 2 × 3
24
64
2 2 3
×
××× 2
60 = 2 × 2 × 3 × 5
60
125
5 3
×
×
2 × 3×5
4×
2×
27 = 3 × 3 × 3
27
93
3 3 3
×
××
200 = 2 × 2 × 2 × 5 × 5
200
1002
2 10
×
×
5 5× 2×2
10
2 ×
×
×
36 = 2 × 2 × 3 × 3
36
94
2 3 3
×
××× 245 = 3 × 3 × 5
45
95
5 3 3
×
××
17 NCM7 2ed SB ANS.fm Page 511 Friday, June 6, 2008 11:19 PM
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3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
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0123456789
1234
512 NEW CENTURY MATHS 7
g
h
10 a 24 = 23 × 3 b 60 = 22 × 3 × 5c 27 = 33 d 200 = 23 × 52 e 36 = 22 × 32 f 45 = 32 × 5 g 72 = 23 × 32 h 144 = 24 × 32
11 a 16 b 81 c 36 d 12112 a 8 b 5 c 7 d 1213 a 8 b 216 c 729 d 51214 a 3 b 4 c 5 d 1015 a
= = 5 × 3= 15
b
= = 2 × 2 × 2 × 2= 16
c
= = 2 × 3 × 7= 42
72 = 2 × 2 × 2 × 3 × 3
72
362
2 6
×
×
2 2× 3×2
6
3 ×
×
×
144 = 2 × 2 × 2 × 2 × 3 × 3
144
364
2
×
2 2× 3×2 3 ×
×
×
2 6 × 6×
×2
225
455
5 9
×
×
5 × 35
5
3 ×
×
×
225 5 5× 3× 3×
256
644
2 2 16
×
× ×
2 2 2×× 4×
2 × 2 2× 2 2××
4×
4×2
2 ×2
×
×2×
256 2 2× 2× 2× 2× 2× 2× 2×
1764
5883
3 147
×
× ×
3 2×× 21×
3 × 2 7 3××
4
7×2
7 ×2×
1764 2 2× 3× 3× 7× 7×
d
= = 2 × 3 × 3= 18
16 7 and 8
Mixed revision 11 15 2 29 3 394 a 6 tens b 6 units
c 6 ten thousands d 6 hundreds5 a 3 × 10 + 8 × 1
b 2 × 102 + 0 × 10 + 1 × 1c 3 × 103 + 9 × 102 + 8 × 10 + 7 × 1
6
7 a 26 b 14 c 188 a 0 b 31 c 11
d 52 e 23 f 609 a True b False c True
d False e False f True10 a 103° b 57° c 295° 11 Teacher to check.12 ∠PSA a vertex b arms13 a 24° b 5° c 78° d 1° 14 a 148° b 90° c 75° d 27° 15
Is one possibility. (Teacher to check.)16 Teacher to check.17 a m° = 130° b b° = 110°
c p° = 142° d a° = 98° e p° = 54° f a° = 88°, b° = 92°g c° = 142° h m° = 55°i m° = 37°, p° = 87° j x° = 296° k x° = 30° l y° = 90°
5832
29162
2 729
×
×
2 2× 81×
2 × 2 3× 9 9×
4×
9×
×3×
2 × 2 3× 3 3××3× 2 3× ×
2 ×
2×
× 3
58323 2 2× 2× 3× 3× 3× 3× 3× 3×3
a 6 12
3 9 15
15 21 27
+ b 17 24
9 8 15
13 4 11
−
c 5 9 4
7 35 63 28
3 15 27 12
8 40 72 32
× d 48 36
4 12 9
6 8 6
÷
12---
17 NCM7 2ed SB ANS.fm Page 512 Friday, June 6, 2008 11:19 PM
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90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
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0123456789
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513ANSWERS
18 a 10, 13, 16 b 10, 15, 21c 8, 13, 21 d 5, 3, 1
19 a 2 and 4 b 2, 3, 6 and 7 c 2, 4 and 8
20 a 1, 2, 3, 6, 9, 18 b 1, 3, 5, 9, 15, 45c 1, 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24,
30, 36, 40, 45, 60, 72, 90, 120, 180, 360
21 a 18 = 2 × 32 b 45 = 5 × 32 c 360 = 5 × 23 × 32
22 a 36 b 27 c 5d 11 e 5 f 4
Chapter 4Start up
1 a Any of the following: triangle, rectangle, square, hexagon, pentagon, trapezium, circle, ellipse
b Teacher to check.2 Teacher to check.3 a 4 b 8 c 3
d 6 e 4 f 54 Parallel lines5 a A rectangular prism B cube
C square pyramid D sphereE cone F triangular prismG triangular pyramid (tetrahedron)H cylinder I hexagonal prism
b Teacher to check.6 a C, F b F c D, E, H
d D e G f F g Bh A, B (because squares are special
rectangles)i C j D, E, G, H
Exercise 4-011 a convex b non-convex
c non-convex d convexe convex f non-convexg convex h non-convexi convex
2 d i cube ii cylinderiii square pyramid iv triangular prismv L shaped prism vi rectangular prism
vii rectangular pyramidviii cone ix T shaped prism
x triangular pyramide i convex ii convex
iii convex iv convexv non-convex vi convex
vii convex viii convexix non-convex x convex
Exercise 4-021, 2 Teacher to check.
3 a rectangle prism b trapezoidal prismc cube d triangular prisme square pyramid f cylinderg triangular prism h rectangular prism
4 A
Exercise 4-031 triangular pyramid2 A tetrapak is a box in the shape of a triangular
pyramid and has four faces. Tetris uses shapes made up of four squares.
3 a, b, d4 a i a cube and a square pyramid
ii polyhedron iii convexb i a rectangular prism and a cylinder
ii It is not a polyhedron.iii not convex
c i a cylinder and a coneii It is not a polyhedron.
iii convexd i a cone and a hemisphere
ii It is not a polyhedron. iii convexe i two triangular pyramids
ii It is a polyhedron. iii convexf i two rectangular prisms
ii It is a polyhedron.iii not convex
5 Teacher to check.
7 48 a 4 b 8 c 6 d 59 a pentahedron b hexahedron
c heptahedron d pentahedrone nonahedron f octahedron
6 Solid
No.of
faces
Shapesof
faces
No. ofidentical
faces
No. of parallel
flat faces
Cube 6 square 6 6
Cylinder 3 circle, rectangle
2 2
Squarepyramid
5 square, triangle
4 0
Triangularprism
5 triangle,rectangle
2 2
Rectangularprism
6 rectangle 3 lots of 2 6
Rectangularpyramid
5 triangle, rectangle
2 lots of 2 0
Cone 2 circle, sector
0 0
Triangularpyramid
4 triangle 0 0
17 NCM7 2ed SB ANS.fm Page 513 Friday, June 6, 2008 11:19 PM
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514 NEW CENTURY MATHS 7
10 D11 Because they all have six faces.12 cube, equilateral triangular pyramid
(Teacher to check others.)
Exercise 4-041 Other answers are possible. (Teacher to
check.)
2 a a, c, d, e, g, h, i, k, lb a, c, e, g, h, i, l c d, kd b, f, j, m, n
3 B4 Teacher to check.5 a i octagon ii octagonal prism
iii right prismb i kite ii kite prism
iii oblique prismc i pentagon ii pentagonal prism
iii right prismd i T-shape or octagon
ii T-prism or octagonal prismiii right prism
e i trapezium ii trapezoidal prismiii oblique prism
f i L-shape or hexagonii L-prism or hexagonal prismiii oblique prism
7 Teacher to check.8 a oblique triangular pyramid
b right hexagonal pyramidc right trapezoidal pyramidd oblique square pyramide oblique square pyramidf right triangular pyramid
a b c
d e f
g h i
j k l
m n
9 a rectangle b triangle c parallelogram10 Teacher to check.11 The base, a circle, is not a polygon.
Exercise 4-051 a i cylinder ii oblique
b i cone ii rightc i sphere ii neitherd i cylinder ii righte i cone ii obliquef i cone ii rightg i trapezoidal prism ii obliqueh i triangular pyramid ii right
2 a A, B, C, D, E, F, H, I, J, K, L, M, N, O, P, R, S, U, V, W, X, Y, Z, AA, CC, DD, FF
b B, E, I, M, O, S, V, Z, BB, EEc A, R, V, Y, AA, DDd C, K, P, R, U, AA, DD, FF
3 B 4 D
Exercise 4-06
2 A3 a F = 7, V = 10, E = 15
b F = 5, V = 6, E = 9c F = 6, V = 8, E = 12d F = 6, V = 7, E = 11
Yes. Euler’s rule does hold true.
4 a triangular prism b cubec pyramid d triangular pyramide rectangular prism
Mental skills 42 Your answers should be close to the following
exact answers.a 331 b 157 c 1587d 255 e 421 f 203g 413 h 734 i 6723j 15 744 k 276l 72.43 (to two decimal places)
1 Polyhedron
No. of faces
(F)
No. of vertices
(V)
No. of edges
(E) F + V
Cube 6 8 12 14
Rectangularprism
6 8 12 14
Triangularprism
5 6 9 11
Triangular pyramid
4 4 6 8
Square pyramid
5 5 8 10
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67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
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78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
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012 3456789014567890123456789012
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567890123 8901234789
0123456789
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515ANSWERS
Exercise 4-071 a HG, CG, FG
b DH, BF, AE c CG, BF, EF, HG
2 D3 Teacher to check.4 a skew, parallel, intersecting, skew
b intersecting, parallel, skew, intersectingc parallel, parallel, skew, intersecting
Exercise 4-081 b 4 c triangular pyramid
d equilateral triangle e 4 f 6g i No ii Yes iii Yes
2 b 8 c equilateral triangled 2 square pyramids e 12f i Yes ii Yes iii Yes
3 b 20 c equilateral triangled 30 e 12 f Yesg i Yes ii Yes
4 b 6 c square d cube5 b 12 c regular pentagon
d 30 e 20 f Yesg i Yes ii Yes
6 D
8 a dodecahedron b tetrahedronc octahedron d icosahedrone hexahedron f dodecahedron
Exercise 4-091 to 4 Teacher to check.
5
7 Platonic solid DescriptionShape ofeach face
No. of faces
Octahedron two square pyramids joined at bases
equilateral triangle
8
Dodecahedron like a soccer ball pattern
regular pentagon
12
Icosahedron like a crystal equilateral 20
Tetrahedron triangular pyramid
equilateral triangle
4
Hexahedron cube square 6
a b
6
7
8 Teacher to check.9 a iv, vii b i c v, x d ii, vi, ix
10 Compare your answers with those of other students. (There are more than five.)
11 D
Exercise 4-101
c d e
A B C
i ii iiia
i ii iiib
i ii iiic
i ii iiid
i ii iiie
i ii iiif
17 NCM7 2ed SB ANS.fm Page 515 Friday, June 6, 2008 11:19 PM
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67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
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78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
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012 3456789014567890123456789012
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567890123 8901234789
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0123456789
1234
516 NEW CENTURY MATHS 7
2
3 D 4 C5 Teacher to check. 6 Teacher to check.
Power plus1 Teacher to check.2 a 16 b 2 c 63 a R = 4, V = 5, E = 7
b R = 2, V = 4, E = 4c R = 3, V = 3, E = 4d R = 8, V = 12, E = 18e R = 1, V = 2, E = 1f R = 4, V = 5, E = 7g R = 4, V = 2, E = 4h R = 2, V = 12, E = 12i R = 12, V = 10, E = 20j R = 6, V = 2, E = 6k R = 6, V = 6, E = 10l R = 2, V = 8, E = 8Euler’s rule for networks is: Number of regions + number of vertices = number of edges + 2
4 a 12 pentagons, 20 hexagons
i iia
i ii iiib
i iid
i iie
iii iv
i iif
i ii iiic
b A semi-regular polyhedron does not have identical faces but all its faces are regular polygons.
5 Teacher to check.
Chapter 4 revision1 a non-convex b convex2 B
4 Teacher to check.5
6 a Oblique pyramidb Oblique T-prism or octagonal prismc Right square pyramidd Right octagonal prisme Oblique triangular prismf Right cylinder
7 5f and 6b8 a D b C c I d F e A
f H g B h E i J j G9 a 5 b 9 c 6
10 Teacher to check.11 A polyhedron with faces that are identical
regular polygons. Regular tetrahedron, Regular hexahedron, Regular octahedron, Regular dodecahedron or Regular icosahedron.
12 a Two square pyramids.b All faces are identical regular polygons, in
this case equilateral triangles.
3 a Solid A Solid B Solid C
No. of faces 5 4 7
No. of congruent faces
2 2 3 lots of 2
Shapes of faces triangle,rectangle
rectangle, semi-circle
pentagon, rectangle
No. of parallelflat faces
2 2 2 lots of 2
Shape of a cross-section
triangle semi-circle pentagon
Are the cross-sections uniform?
Yes Yes Yes
Is the solid a polyhedron?
Yes No Yes
a b c
d e f
Prism
Not a prism Not a prism
Not a prismPrism
Prism
17 NCM7 2ed SB ANS.fm Page 516 Friday, June 6, 2008 11:19 PM
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517ANSWERS
c Number of faces = 8, number of vertices = 6, number of edges = 12
d Number of faces + number of vertices = number of edges + 2
8 + 6 = 12 + 2
14
12
Chapter 5
Start up1 a 16 b 8 c 28 d 4
e 21 f 25 g 22 h 5i 13 j 8 k 15 l 6
2 a 49 b 604 c 110 d 33e 237 f 128 g 23 h 2i 28 j 400 k 12 l 32
3 a T b T c F d T e Ff F g T h T i T
4 a 1, 2, 3, 4, 8 b 2, 3, 5, 7, 16, 18c 27, 38, 49, 51, 54, 66
5 a 18, 17, 11, 6, 5, 3 b 31, 23, 14, 8, 7, 5, 2c 91, 89, 69, 46, 41, 37, 3
6 a 9 b 8 c 25 d 27
Exercise 5-011 A = 4, B = 9, C = 11, D = 17, E = 20, F = 272 a A = 2, B = 10, C = 13, D = 15
b A = 10, B = 16, C = 28, D = 34, E = 37c A = 8, B = 15, C = 32, D = 41, E = 49, F = 56d A = 4, B = 36, C = 52, D = 66, E = 90,
F = 116e A = 10, B = 20, C = 35, D = 55, E = 63,
F = 89, G = 1113 a 88°C b 35°C4
a b
i ii iiia
i ii iiib
i ii iiic
15129630
5
6
7 a 15, 18, 21 b 22, 23, 24c 112, 113, 114 d 75, 74, 73e 30, 29, 28 f 158, 157, 156g 4, 3, 2 h 15, 13, 11
8 a 29 b 35 c 44 d 20 e 15 f 59 30°C 10 16°C
Exercise 5-021 a i about 38 metres ii about 73 metres
iii about 111 metresb ‘+’ signs measure height above water level
and ‘−’ signs measure depth below water level
2 a 37°C b 0°Cc about −72°C d 117°C
3 $3944
5 a −40 000 would mean 40 000 years ago from today.
b Teacher to check.c Traditionally, the zero for time is when
Jesus Christ was born. BC, meaning Before Christ, refers to the time before Christ. AD, meaning Anno Domini, refers to the time after Christ was born. These days, BCE (Before the Common Era) and CE are often used instead of BC and AD.
d Answers vary. Should be your age now.e Teacher to check.
6 In 27 BC, Christ had not been born, so nobody could have known to pre-record this event with the date 27 BC. The coin must be a fake or the archeologists are lying.
Exercise 5-031 a Missing values are −5, −4, −2, 4, 5, 7, 8
b Missing values are −50, −40, −30, 20, 30, 50, 60, 70
c Missing numbers are −35, −30, −25, −20,−15, −10
d Missing numbers are −400, −300, −200, 200e Missing numbers are −33, −30, −27, −24, −21,
−18, −15, −12, −9, −62 a � b � c � d � e � f �
g � h � i � j � k � l �
m � n � o � p � q � r �
3 a −6 b −1 c 10d −11 e 0 f 2
129630 1 4 5 7 8 10 11
9630 1 4 5 7 8 102
500 0 500BC AD
A B C D E F G H I J
17 NCM7 2ed SB ANS.fm Page 517 Friday, June 6, 2008 11:19 PM
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518 NEW CENTURY MATHS 7
4 a down b less c upd right e descending f northg deposit h increase i east
5 a 7 b −8c −8, −6, −4, −2, 1, 3, 5, 7
6 a −3, −1, 2, 3 b −8, −5, −3, 2, 5c −10, −6, −4, −3, 0 d −5, −3, −2, 4, 6e −48, −24, −11, 0, 8, 36f −26, −10, −2, 3, 12, 15
7 a 5, 4, 3, −1, −2 b 8, 0, −2, −4, −7c 4, 1, −1, −3, −5, −11d 8, 3, −2, −4, −18e 1, −3, −6, −15, −48f 33, 1, −36, −58, −100
8 a 2 b 2 c 4 d 3e 6 f 20 g 7 h 7
9 D10 a −4 b −6 c 4 d −2 e −12
Exercise 5-041 a 15 b −1 c 3 d −7
e 0 f 3 g −11 h −4i −26 j 20 k −8 l 0m −2 n −9 o −1 p 6
2 a 2 b 1 c −11 d 6e 12 f −1 g 0 h −10i −10 j 5 k −6 l 6m −13 n −6 o 12 p −9
3 a 0 b 0 c 7 d −20e −5 f −14 g 70 h −21i −19 j 8 k −32 l 8
4 a 11 b −11 c 29 d −29e −11 f 3 g 16 h −10i −8 j 8 k 10 l −10
5 a −7 b 6 c −4 d 1e −5 f 31 g 26 h −178i 120
6 B 7 C8 a −10 b −4 c −2 d 0
e −14 f −10 g −8 h −49 a −10 b −14 c −20 d −21
e −10 f −2 g 7 h 610 a −7 b 3 c −3 d −7
e 7 f −7 g −6 h 6i 20 j −16 k −9 l 5
11 a + −2 −7 −10 b + −3 −5 6 5
4 2 −3 −6 4 1 −1 10 9
−5 −7 −12 −15 −2 −5 −7 4 3
8 6 1 −2 6 3 1 12 11
−11 −14 −16 −5 −6
Mental skills 5A2 a 155 b 221 c 317 d 1764
e 48 f 726 g 283 h 952i 722 j 631 k 215 l 163
m 394 n 466 o 937 p 295
Exercise 5-051 a 6610 m b 2316 m
c 311 m d 9237 m2 13°C 3 4 km west4 7 km 5 4602 m6 155 m7 a 2002, 2003, 2006, 2007
b 2004, 2005 c $100 milliond Profit, $200 million
8 11 m 9 −$7 10 A
Exercise 5-061 a −18 b −24 c 21 d −32
e 63 f −45 g 42 h 42i −24 j −9 k 1 l −54m −10 n −42 o 44 p −81q 60 r −60 s 100 t 56
2 C 3 A4 D
6 a 24 b 30 c 81d −33 e −16 f −243g 18 900 h 4160 i −99 000j 5600 k −1 l −52
m −30 000 n −16 o 36p 90 q 112 000 r −1300s 0 t 360
c + 2 3 4 d + 3 −4 5 −2 6 −6
−1 1 2 3 1 4 −3 6 −1 7 −5
2 4 5 6 −3 0 −7 2 −5 3 −9
−3 −1 0 1 −4 −1 −8 1 −6 2 −10
6 9 2 11 4 12 0
5 a × −3 5 b × −5 5
−3 9 −15 5 −25 25
5 −15 25 −5 25 −25
c × 6 −4 d × −1 1
−4 −24 16 −1 1 −1
6 36 −24 1 −1 1
e × 7 −3 f × −3 −6
4 28 −12 8 −24 −48
−6 −42 18 2 −6 −12
17 NCM7 2ed SB ANS.fm Page 518 Friday, June 6, 2008 11:19 PM
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519ANSWERS
7 a 16 b 9 c 49d −128 e 125 f −8g 4 h −200 i 216
8 Negative9 a −48 b 44 c 240
d −65 e −418 f 300g 25 h −512 i −735
Exercise 5-071 a −3 b −2 c 4 d −3
e −9 f 3 g −4 h −50i −4 j 17 k −9 l −12m 16 n −5 o −14 p −6q −3 r 20
2 a −6 b −2 c 6 d 33e −21 f −9 g 20 h 9
3 A 4 B
6 a −20 b −2 c −21 d 3e −200 f 28 g −23 h 27i 3 j 42 k 4 l 13m −200 n 5
7 a −10 b 112 c 1 d 1440e −6 f −20 g −48 960 h −192
Exercise 5-081 a −2 b 2 c −12 d 2
e −14 f −25 g −21 h −3i 11 j 8 k −6 l −9m −3 n −22 o −1 p −5
2 a −18 b 12 c 9 d −2e 50 f 5 g −48 h −8i 10 j 1 k 30 l 10m −16 n 8 o −4
3 C4 a −7 b −25 c −36
d 10 e 14 f 3g 5 h 8 i 2j 8 k −11 l 2
5 a −38 b 10 c 84d 133 e 117 f −204g −16 h −3 i 5j −6 k 3 l 1m −26 n −9 o 15p 22 q 11 r 42
6 a Correct b Incorrect, 6 − 8 = −2c Incorrect, −6 − 8 = −14d Correct e Correct
5 a ÷ −6 −3 3 6 b ÷ 8 −8 32 −32
−6 1 − −1 −2 −4 4 −16 16
−3 2 1 −1 −2 4 2 −2 8 −8
12-- 1
2--
f Incorrect, (−2 + 6) × 2 = 8g Incorrect, −7 − 6 + 10 = −3h Incorrect, (−12 − 3) ÷ (−3) = 5i Incorrect, 12 − 3 × 5 = −3j Incorrect, 2 − 9 × (−3) − (−18) = 47
7 a −19 b −84 c 34d 1 e −60 f −17g 74 h 61 i 16
Mental skills 5B2 a 17 b 35 c 114 d 261
e 132 f 128 g 56 h 418i 74 j 123 k 88 l 112
m 36 n 549 o 185 p 317
Exercise 5-091 A(1, 4), B(2, 2), C(3, 1), D(3, 4), E(4, 3),
F(5, 2), P(6, 5)2 M(0, 2), P(1, 1), A(2, 0), B(2, 3), N(3, 1),
J(3, 3), E(4, 0), U(5, 2)3
A cube or block has been drawn.4 a NUMBER b PLANE
c WATER d METREe NURSE f UMPIRE
5 a, b
6
5
4
3
2
1
01
2
3 4 5 6
8
654
2
10
1
3
4 5 6 83 7 9 10 11 12 13 14 15 x
y
2
7
91011121314151617181920
17 NCM7 2ed SB ANS.fm Page 519 Friday, June 6, 2008 11:19 PM
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520 NEW CENTURY MATHS 7
c A sailing boat.6 a, b
c A dog7 a swimming pool b golf course
c park d shops, car yarde car park f tennis courts
8 a E3 b C3 c C4d F4, G4 e F3, G3 f C3
Exercise 5-101 A(−4, 3) B(−2, 2) C(0, 2) D(2, 3)
E(2, 1) F(1, −1) G(2, −3) H(0, −3)I(−4, −3) J(−2, −1) K(3, 0) L(−4, 0)M(0, −2) N(0, 3) O(0, 0) P(−2, 0)Q(1, 0) R(3, −2) S(−2, −2) T(−3, 1)U(−1, 2) V(4, 1) W(4, −3) X(−4, −1)Y(1, −4) Z(−1, −3)
2
1 20
x
y
3 4 5 6 7 8 9 10 11 12
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
6
5
4
3
2
1
5
4
6321−3 −2 −1−4−5−6 −1−2
−4
−5−6
−3
AM
FG
P
ED
K
J
I H
B
C
NQ
L
0
3 a A, M b B, C, N, Qc D, K, J d F, G, Pe E, I, H, L
4 a Fourth b Third c Second
6 a, b
c The points form a straight line.7 a, b
c A bear.
Power plus1 a −8 b −64 c −32
d −1 e −1 f 1g −324 h 2 i −2j 2 k −2 l −1
2 a 4 or −4 b 10 or −10 c −23 Teacher to check.
4 a 2 b −9 c −1
5 Points in: x-coordinate y-coordinate
1st quadrant + +
2nd quadrant - +
3rd quadrant - −
4th quadrant + −
3
2
1
−1
−2
−3
−1−2−3 1 2 3
A
B
C
D
E
F
y
x0
10
10
–10
–10 x
y
17 NCM7 2ed SB ANS.fm Page 520 Friday, June 6, 2008 11:19 PM
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521ANSWERS
5a, b
d A cat.
Chapter 5 revision1 a
b
c
2 a 1, 2, 3 b −2, −3, −4c −10, −12, −14 d −4, −6, −8e −4, 5, −6 f −7, −9, −11
3 a −$109 b −$50.954 a F b F c F d T
e T f T g T h Fi F j F k T l F
5 a 2 b 23 c −56 d 10e −8 f 0
6 a −1 b 7 c −10 d −3e 4 f 18 g −12 h 0i −15 j 3 k −11 l −7m 6 n −2 o −22 p −8q 17 r −11
7 16°C8 a −18 b 48 c −10
d −400 e −63 f 48g −24 h −42 i 40
9 a 3 b −3 c 1d −4 e −2 f −100g 2 h −3 i 8
10 a −12 b −22 c −13 d −18e 0 f −19 g 7 h −2
65
4
321
5
4
6321-3 -2-4-5-6 -1-2
-4-5-6
-3
789
10
-8-7
7 x-7
y
1112
630 1 4 5 72
630 1 4 5 72
630 1 4 5 72
11 Correct answers are:a −9 b −1 c −6 d 6e −20 f 0 g −1 h 2i −73 j 24Thus the student was correct in parts a, d, e, h, j. Score: 5 out of 10
12
13 A(2, 0) B(3, 2) C(0, 4) D(−2, −1)E(1, −3) F(−1, 1) G(4, 1) H(−4, 3)I(0, −5) J(−3, 0) K(3, −4)
14 a Third b Teacher to check.c Fourth d Teacher to check.e (0, 0)
15 a
b An octagon.
16 a
b A rocket ship.
6
5
4
3
2
1
01
2
3 4 5 6
F
E
D
B
A
C
4321 x
3
2
1
4
−2−1
−2
y
−1
5
5−3
−3
0
432 x
3
2
1
4
−4−1
−2
−4
y
5
−3
7
1−2 −1
−3
6
0
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522 NEW CENTURY MATHS 7
Chapter 6
Start up1 a 8 b 4 c 6 d 15
e 2 f 30 g 6 h 9i -3 j -3 k -1 l -7
2 a 6 b 12 c 6 d 20e 10 f 9 g 7 h 11i -4 j 7
3 a 4 b 5 c 9 d 7e 4 f 8 g 4 h 4i 8 j 4 k 50 l 2
4 a 16 b 30 c 7 d 3e -11 f 17 g 1 h 14i 16 j 7 k -5 l 21
Exercise 6-011 a, b, c, and d
e The number of toothpicks equals 3 times the number of triangles.
f Teacher to check. g 3002 a, b, and c
d The number of toothpicks equals 4 times the number of diamonds.
e Teacher to check. f 3203 a, b, and c
d The number of toothpicks equals 6 times the number of hexagons.
e Teacher to check. f 2404 a, b, and c
d The number of toothpicks equals 3 times the number of squares plus 1.
e Teacher to check. f 1515 a, b, and c
d The number of toothpicks equals 2 times the number of triangles plus 1.
e Teacher to check. f 201
Number of triangles 1 2 3 4 5 6
Number of toothpicks 3 6 9 12 15 18
Number of diamonds 1 2 3 4 5 6
Number of toothpicks 4 8 12 16 20 24
Number of hexagons 1 2 3 4 5 6
Number of toothpicks 6 12 18 24 30 36
Number of squares 1 2 3 4 5 6
Number of toothpicks 4 7 10 13 16 19
Number of triangles 1 2 3 4 5 6
Number of toothpicks 3 5 7 9 11 13
6 a, b, and c
d The number of toothpicks equals 5 times the number of hexagons plus 1.
e Teacher to check. f 1017 Teacher to check.
Exercise 6-021 a 5 b 15 c 252 a 7 b 21 c 283 a 4 b 10 c 164 a 5 b 11 c 1135 a 5 b 45 c 4956 a 14 b 68 c 4767 a 9 b 2500 c 10 0008 a 22 b 42 c 3029 a 13 b 48 c 248
10 a 151 b 2507 c 640711 C 12 1013 8 14 9
Exercise 6-031 a n = 5 × s b n = 7 × s
c n = 3 × s + 1 d n = 4 × s + 2e n = 2 × s + 3 f n = 10 × s − 5
2 Teacher to check. 3 A4 Teacher to check.
Exercise 6-04
Number of hexagons 1 2 3 4 5 6
Number of toothpicks 6 11 16 21 26 31
1 a x 3 7 1 8 4 5
y 2 6 0 7 3 4
b p 8 3 2 5 10 4
q 24 9 6 15 30 12
c m 6 4 11 5 8 3
n 4 2 9 3 6 1
d x 2 11 7 0 13 9
y 9 18 14 7 20 16
e a 8 1 5 0 4 2 9
b 16 2 10 0 8 4 18
f x 10 4 7 5 8 9 6 11
y 7 1 4 2 5 6 3 8
2 a p 3 8 2 6 0 4 1 14
r 5 10 4 8 2 6 3 16
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523ANSWERS
3 D
Exercise 6-051 a b = t − 2 b k = p + 4 c y = x − 3
d j = 2 × h e p = m ÷ 52 a b = 3 × a; 12, 3 b n = k − 4; 2, 5
c w = u ÷ 2; 7, 1 d y = x − 3; 7, 8e b = 3 × t; 21, 24 f f = e + 5; 15, 16g v = 8 × u; 48, 56 h f = 3 × e; 12, 24i r = p + 7; 8, 16
Exercise 6-061 a h = 3 × f − 2; 19, 22
b p = 5 × m − 3; 32, 37c b = 3 × m + 3; 21, 24d k = 2 × h + 2; 20, 22e s = 3 × r + 1; 19, 22f b = 2 × a − 2; 14, 16
2 a n = 3 × m + 5; 23, 26b d = 10 × c + 1; 71, 81c x = 5 × w − 1; 34, 39d z = 2 × y − 6; 12, 14e m = 4 × a + 1; 29, 33f t = 2 × z − 7; 13, 15g a = 3 × d + 4; 22, 25h h = 2 × g − 2; 12, 6i k = 3 × j − 2; 13, 10j t = 10 × w − 1; 79, 99
3 D
b t 7 11 2 0 8 12 5 9
w 14 22 4 0 16 24 10 18
c a 4 5 7 2 0 10 8 6
b 12 15 21 6 0 30 24 18
d h 12 8 2 6 0 4 10 16
k 6 4 1 3 0 2 5 8
e m 3 10 1 4 8 6 2 12 9
p 14 49 4 19 39 29 9 59 44
f p 4 1 8 5 7 10 2 6
q 10 1 22 13 19 28 4 16
g r 2 0 3 9 5 4 1 6
t 9 1 13 37 21 17 5 25
h y 4 8 1 0 7 5 6 2
z 22 42 7 2 37 27 32 12
i h 2 8 5 4 0 3 1 6
g 4 64 25 16 0 9 1 36
Exercise 6-07
1 a 6m b c p d 3y
e f ab g n h d
i pq j k 2d + 7 l 9 − 2k
m y2 n a3 o 2a4
2 a 9 × m b h ÷ 4 c 14 × yd 6 ÷ p e 3 × k + 2 f 1 × fg e × f h d × w ÷ 4 i 1 × yj 5 × a × m k 5 × y ÷ 7 l 16 − 3 × g
3 A4 i a p equals 2 times m b p = 2m
ii a k equals h minus 2 b k = h − 2iii a b equals 3 times a b b = 3aiv a y equals 2 times x plus 1 b y = 2x + 1
Mental skills 6A2 a 108 b 154 c 166 d 210
e 52 f 82 g 196 h 324i 91 j 137 k 46 l 69m 253 n 38 o 24 p 85
Exercise 6-081 a
c The number of pieces of cake equals twice the number of cuts through the cake.
d p = 2 × c e i 100 ii 200f The rule is accurate but, in practice, it is
not possible to make a large number of cuts accurately.
2 a
b No. of cuts, c 1 2 3 4 5 7 9
No. of pieces, p 2 4 6 8 10 14 18
b Arm length, a 1 2 3 4 5 7 9
No. of tiles, t 4 7 10 13 16 22 28
k7---
s9---
my6
-------
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524 NEW CENTURY MATHS 7
c The number of tiles equals 3 times the arm length plus 1.
d t = 3 × a + 1e i 121 ii 211
3 a
c The number of toothpicks equals 5 times the number of flight shapes plus 2.
d t = 5 × f + 2e i 202 ii 502
4 a
c The number of toothpicks equals 3 times the number of rocket stages plus 2.
d t = 3 × s + 2e i 182 ii 302
Exercise 6-091 a i 18 ii 8 iii 8 iv 60
b i 0 ii 22 iii 1c i 32 ii 12 iii 10d i 16 ii −3 iii −24e i 72 ii 96 iii −12
b No. of flights, f 1 2 3 4 5 7 9
No. oftoothpicks, t 7 12 17 22 27 37 47
b No. of stages, s 1 2 3 4 5 7 9
No. of toothpicks, t 5 8 11 14 17 23 29
2 a x 0 3 10 4 7 6 2 5
y 0 12 40 16 28 24 8 20
b d 4 16 10 2 8 14 12 11
h 2 8 5 1 4 7 6 5.5
c x 2 7 8 5 10 4 3 6
y 1 11 13 7 17 5 3 9
d b 1 4 9 2 7 5 10 3
c 3 12 27 6 21 15 30 9
3 a i d = 10 ii d = 22 iii d = 30b i b = 14 ii b = 35 iii b = 59c i z = 2 ii z = 8 iii z = 15d u = 9 e p = 1 f k = 36
Exercise 6-101 i −15 ii −8 iii 102 b = −13 3 w = −124 p = −14 5 B6 a = −8 7 m = 2
e e 12 16 8 4 10 2 6 20
f 3 4 2 1 2.5 0.5 1.5 5
f r 0 1 2 3 4 5 6 7
s 12 11 10 9 8 7 6 5
g j 3 4 6 8 2 10 5 9
k 8 11 17 23 5 29 14 26
h d 8 2 1 4 3 7 0 6
f 21 9 7 13 11 19 5 17
i m 7 2 6 5 4 10 1 3
n 67 17 57 47 37 97 7 27
j v 27 6 12 0 30 15 9 18
w 9 2 4 0 10 5 3 6
k m 5 2 1 10 4 7 8 11
p 29 11 5 59 23 41 47 65
l t 3 1 7 2 5 8 10 6
v 8 0 48 3 24 63 99 35
8 a x 7 2 5 0 −2 −5 12 10
y −3 −8 −5 −10 −12 −15 2 0
b m 1 −1 −3 0 4 −6 −4 −10
p 4 −2 −8 1 13 −17 −11 −29
c a 3 0 1 −4 −2 2 −6 −1
b 7 4 5 0 2 6 −2 3
d t 4 8 −4 −1 6 −3 −5 1
u −5 −1 −13 −10 −3 −12 −14 −8
e r −3 −2 −1 0 1 2 3 4
s −12 −10 −8 −6 −4 −2 0 2
f n 3 5 0 −2 −4 −1 −5 6
p 10 12 7 5 3 6 2 13
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525ANSWERS
Mental skills 6B2 a 56 b 108 c 64 d 420
e 344 f 128 g 224 h 264i 46 j 68 k 140 l 108m 78 n 39 o 32 p 19
Power plus1 b Teacher to check.
ii The number of chairs equals 3 times the number of tables plus 2, c = 3t + 2
d i 26 ii 47 iii 59
3 a y = 25 − x b y = 50 − 2xc w = 60 − 5v
4 Teacher to check.
Chapter 6 revision
2 a 7 b 11 c 373 a g = 3c b e = 6s + 3
9 a x 2 5 −1 4 −3 0 1 6
y −2 4 −8 2 −12 −6 −4 6
b j 1 −1 −5 5 0 3 −2 −7
k 1 1 25 25 0 9 4 49
c v 3 0 8 6 10 −3 7 −1
w 7 10 2 4 0 13 3 11
d n 1 −1 −3 3 0 −5 −7 7
m 2 1 0 3 1.5 −1 −2 5
c i Number of tables, t 1 2 3 4
Number of chairs, c 5 8 11 14
2 a h 2 3 4 5 10 20 1000
f 9 14 19 24 49 99 4999
b A 0 1 2 3 5 10 100
B 1 2 5 10 26 101 10 001
c x 0 1 2 3 4
y 2 5 8 11 14
x 10 20 30 33 1000
y 32 62 92 101 3002
1 Lanes on bridge 1 2 3 4 5
Number of tiles 5 6 7 8 9
Lanes on bridge 7 9 12 50 100
Number of tiles 11 13 16 54 104
5 a y = x − 2 b b = 7 × ac n = m ÷ 4 d t = r + 4
6 p = 3m − 17 a 4p b ad c
b The number of fence sections equals 5 times the number of paddocks plus 2.
c f = 5p + 2 d 502
s = 4t + 1b 85
10 a
c The number of triangles equals 2 times the number of dots, minus 4.
d t = 2d − 4e i 24 ii 96
4 a m 1 3 12 0 7 4 2 11
n 5 15 60 0 35 20 10 55
b p 10 7 11 15 20 18 14 30
q 3 0 4 8 13 11 7 23
c c 2 12 5 3 7 20 9 6
d 2 32 11 5 17 56 23 14
8 a No. of paddocks, p 1 2 3 4 5 6 7
No. of fence sections, f 7 12 17 22 27 32 37
9 a No. of houses, t 1 2 3 4
No. of sticks, s 5 9 13 17
b No. of dots, d 2 4 6 8 10
No. of triangles, t 0 4 8 12 16
11 a g 1 3 5 7 120
f 6 8 10 12 125
b A 5 6 7 10 30
B 13 16 19 28 88
c A 1 2 3 78 89
B 15 20 25 400 455
d x 1 5 10 12 20
y 195 175 150 140 100
12 a k 2 −2 6 −4 −8 12 −10 −20
j 4 2 6 1 −1 9 −2 −7
b p 3 −1 −3 6 0 −2 1 −5
q 5 −11 −19 17 −7 −15 −3 −27
mn----
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526 NEW CENTURY MATHS 7
Mixed revision 21 a A, D, E, G b C, H
c B, F d A, C, D, E, G, H2 a Rectangular prism b 6
c 12 d rectangle3 Teacher to check.4 a i 6 ii 8 iii 12
b Yes. F + V = E + 2, 6 + 8 = 12 + 25 Teacher to check.6
7
8 −4, −3, −1, 0, 1, 2, 39
10 a 2 b 8 c 411 a −2 b 6 c −7 d −6
e 15 f −3 g 9 h −16i −11 j −26 k 10 l 15
12
13 a i 5 ii 13 iii 21
c n = 4 × s + 1 d 16114 a 40 b 400 c 2400
b s 1 2 3 4 5
n 5 9 13 17 21
15 a k 2 4 −1 0 −3 1
m 5 7 2 3 0 4
430−3−6 −5 −2 −1 1 2−4
a i ii iii
b i ii iii
6
4
2
x
4
2−2−4-2
-4D
F
7
C
A
E
B
y
0
16 a g = f − 2 b n = 3 × m + 2
Chapter 7Start up
1 a 8, 17, 21, 32, 34 b 23, 26, 33, 54, 66c 99, 100, 101, 102, 110, 111d 244, 247, 251, 254, 256
2 a 45, 44, 42, 40, 39, 38b 56, 55, 53, 52, 50, 49c 1111, 1100, 1010, 1001, 1000d 318, 310, 301, 299, 295
3 a 30 b 800 c 9000d 17 000 e 29 500 f 40 220
4 a 611 b 2825 c 324d 49 756 e 189 f 693g 859 h 77 793 i 174j 1008 k 7657 l 20 514m 365 n 309 o 516
5 a 320 b 57 800 c 325 000d 4000 e 40 f 12g 1000 h 810
6 a 700 b 7 c 70d 7000 e 70 000 f 70
Exercise 7-01
b p 12 9 6 3 0 −3
q 4 3 2 1 0 −1
c x 5 1 3 −2 0 −4
y 6 −2 2 −8 −4 −12
d a 3 5 10 −1 6 0
b 18 10 −10 34 6 30
1
Hu
nd
red
s
Ten
s
Un
its
ten
ths
hu
nd
red
ths
tho
usa
nd
ths
a 1 4 8 2
b 6 0 1 4
c 9 3 1 0 2
d 7 0 8
e 2 9 7 8 6
f 1 1 1 4
g 5 0 3 9 2
h 8 3
i 0 3 7 5
j 2 0 0 0 4 7
k 4 0 2 5
l 0 8 1
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527ANSWERS
2 a 5.4 b 6.15 c 8.3d 11.38 e 14.06 f 402.003g 6.23 h 3.7 i 19.9j 14.39 k 24.09 l 2.06m 8.75 n 0.73 o 0.009p 0.859
3 a 1 × 1 + 2 × + 3 × + 4 ×
b 1 × 100 + 0 × 10 + 2 × 1 + 3 × + 4 ×
c 3 × 10 + 0 × 1 + 1 × + 2 ×
d 7 × + 5 × + 1 ×
e 2 × 1 + 0 × + 9 ×
f 1 × 10 + 2 × 1 + 7 × + 1 ×
g 8 × 1 + 0 × + 0 × + 3 ×
h 4 × 1 + 5 × + 0 × + 9 ×
i 0 × + 4 ×
j 3 × + 8 × + 6 ×
4 C5 a 4 hundreds b 4 hundredths
c 4 hundredths d 4 unitse 4 thousandths f 4 tenthsg 4 thousandths h 4 ten-thousandsi 4 thousandths j 4 hundredthsk 4 hundredths l 4 units
6 a 7 tenths b 7 thousandthsc 7 hundreds d 7 hundredthse 7 tenths f 7 unitsg 7 ten-thousandths h 7 tensi 7 tens j 7 tenthsk 7 ten-thousandths l 7 hundredths
7 a 4.1 b 3.8 c 4.35d 12.93 e 5.279 f 0.0461g 19.009 h 2.703 i 11.6002j 3.27 k 270.61 l 76.05
m 0.341 n 0.907 o 27.23p 40.09 q 9.041 r 500.403
Exercise 7-021 a 43.4 L b 139.9c
c $50.00 d $20.00e $9.30 f 1.88 mg 14.4 kg h 15.0 cmi 20.0 kg j 0.25 kgk 85.0 km/h l 2300.0 mm 10.5 m n 8.0 mo 1.1 times p 13.4 kmq 250.0 km r 3.00 h
110------ 1
100--------- 1
1000------------
110------ 1
100---------
110------ 1
100---------
110------ 1
100--------- 1
1000------------
110------ 1
100---------
110------ 1
100---------
110------ 1
100--------- 1
1000------------
110------ 1
100--------- 1
1000------------
110------ 1
100---------
110------ 1
100--------- 1
1000------------
Exercise 7-031 a 2 b 3 c 4 d 3 e 5
f 1 g 6 h 5 i 72 A3 a 9.998, 23.89, 43.89, 56.314, 56.324, 80.879,
400b 0.0586, 0.099, 0.568, 0.586, 0.684, 1.002,
5.608c 0.222, 0.89, 0.891, 1.23, 1.814, 7.007d 0.005, 0.05, 0.5e 3.004, 3.044, 3.4, 3.404, 3.44, 3.441f 0.022, 0.2, 0.202, 0.22g 1.002, 1.01, 1.012, 1.21h 0.007, 0.07, 0.67, 0.71, 7
4 a 4000.99, 1256.3, 570.25, 400.099, 125.63, 0.9899
b 6.539, 5.639, 5.37, 5.369, 5.367, 3.66, 3.659c 1.61, 1.601, 1.6, 1.599, 1.509d 6.6, 6, 0.6, 0.06e 7.07, 0.77, 0.707, 0.7, 0.07, 0.007f 0.44, 0.404, 0.4004, 0.044g 0.65, 0.1, 0.08, 0.029h 0.921, 0.92, 0.099, 0.09
5 a 0.2 � 0.25 b 0.731 � 0.73c 0.035 � 0.305 d 0.007 � 0.070e 1.59 � 1.059 f 0.099 � 0.99g 44.44 � 4.444 h 0.7932 � 0.7239
6 a
b
c
d
e
f
g
7 Teacher to check.
Exercise 7-041 a 0.7 b 0.5 c 0.5 d 0.42 B3 a 0.9 b 0.15 c 0.79
d 0.6 or 0.60 e 0.4 f 0.23g 0.6 h 0.411 i 0.704 j 0.87k 0.07 l 0.14 m 0.8 n 0.235o 0.247 p 0.17 q 0.368 r 0.9345s 0.493
2.41.6 1.7 1.9 2.0 2.32.2
4.123.95 3.98 4.03 4.094.07
3.99
4.05
4.11
0.710.62 0.63 0.65 0.690.67
8.28.0 8.02 8.06 8.128.1 8.16
0.250.07 0.11 0.210.13 0.23
2.61.9 2.0 2.42.1 2.2
4.84.3 4.4
4.45
4.74.5 4.6
4.55 4.675 4.75
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528 NEW CENTURY MATHS 7
4 a 0.67 b 0.3 c 0.04d 0.011 e 0.08 f 0.006g 0.01 h 0.32 i 0.005j 0.0017 k 0.02 l 0.057m 0.0033 n 0.000 46 o 0.000 007
5 a 1.67 b 4.47 c 23.9d 6.8 e 45.023 f 2.3g 6.011 h 89.143 i 42.0 or 42j 5.00 or 5 k 4.006
6 a b c d
e f g h
i j k l
m n o p
q r 1 s 27 t 2
u 10 v 7 w 101 x 6
Mental skills 7A2 a 160 b 130 c 60 d 140
e 210 f 270 g 190 h 220i 300 j 170 k 80 l 290
Exercise 7-051 a 12.0 b 16.933 c 167.317
d 2.1376 e 591.132 a 41.493 b 5.9 c 6.69
d 9.06 e 38.6493 C4 a 117.42 b 54.98 c 57.55
d 3.46 e 64.083 f 10.55 a 81.03 m b 18.97 m6 a Total = $9.54, Change = $0.46
b Total = $15.15, Change = $4.85c Total = $34.72, Change = $15.28
7 18.5 km 8 8037.2 kg9 a 12.45 s, 12.7 s, 13.5 s, 13.81 s, 14.62 s
b 2.17 sc Yes, 12.7 − 0.3 = 12.4 s, which is faster than
12.45 s.10 a $605.55 b $15.2511 10.38 cm 12 6.23 m13 738.9 km
Exercise 7-061 a 1, right b 2, right c 3, right
d 1, left e 2, left f 32, left2 a 4.63 b 5.07 c 1.203
d 0.364 e 0.705 f 310.2g 0.006 43 h 0.0643 i 0.004 28
710------ 4
10------ 39
100--------- 572
1000------------
31000------------ 5
100--------- 11
100--------- 309
1000------------
910------ 999
1000------------ 13
1000------------ 4
10 000----------------
47110 000---------------- 3333
10 000---------------- 5001
10 000---------------- 91
100---------
871000------------ 9
10------ 33
100--------- 7
1000------------
3491000------------ 41
100--------- 3
10------ 102
10 000----------------
j 0.66 k 0.000 31 l 0.002m 2490 n 8.1 o 37 420p 41.6 q 81 r 2192s 6 045 100 t 602 u 0.31
3 a 4521.3 b 10 640c 63.04 d 0.005 98e 84 761.2 f 0.592g 0.3628 h 519 400i 4.0075 j 0.081 348k 50 200 l 0.0061m 0.0004 n 1701o 123 000 p 0.0066q 0.52 r 1.471
4 a 4.691 87 b 0.437 421c 0.000 027 43 d 1.2e 23 500.0137 f 13.7429
Exercise 7-07
2 a 214 200 b 2.142 c 2142d 2142 e 214 200 f 21 420
3 a 20.4 b 204 c 0.204d 20 400 e 2.04 f 2040
4 a 244.8 b 244.8 c 2.448d 2448 e 2.448 f 244 800
5 a 75.6 b 756 c 0.756d 0.756 e 0.0756 f 75 600 000
6 a 0.72 b 0.72 c 7.2d 7.2 e 720 f 0.0072
1 a Multiplication Estimate Answer
69 × 18 1242
690 × 180 700 × 200 = 140 000 124 200
6.9 × 180 7 × 200 = 1400 1242
6.9 × 1.8 7 × 2 = 14 12.42
690 × 1.8 700 × 2 = 1400 1242
b Multiplication Estimate Answer
104 × 42 4368
10.4 × 42 10 × 40 = 400 436.8
1.04 × 4.2 1 × 4 = 4 4.368
104 × 4.2 100 × 4 = 400 436.8
0.104 × 4.2 0.1 × 4 = 0.4 0.4368
c Multiplication Estimate Answer
38 × 92 3496
3.8 × 9.2 4 × 9 = 36 34.96
38 × 920 40 × 900 = 36 000 34 960
38 × 0.92 40 × 0.9 = 36 34.96
380 × 0.92 400 × 0.9 = 360 349.6
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529ANSWERS
Exercise 7-081 a 2 b 1 c 0 d 3 e 3 f 3
g 4 h 3 i 4 j 4 k 6 l 22 a 12.2 b 7.14 c 18.009
d 34.2 e 22.5 f 12.6g 34.75 h 8.0032 i 0.9j 4.8 k 0.012 l 12.6m 32.823 n 59.04 o 40.15
3 a 0.32 b 1.95 c 0.48d 0.072 e 0.0032 f 1.24g 0.756 h 0.84 i 3.51j 0.879 k 27.2 l 10.8
4 a 1101.7 b 46.296 c 525.42d 482.46 e 72.68 f 2.707 56
Exercise 7-091 Total = $45.35, Change = $4.652 Total = $39.25, Change = $10.753 Total = $28.30, Change = $21.704 Total = $39.95, Change = $10.055 Total = $48.85, Change = $1.156 Total = $40.35, Change = $9.657 Total = $31.15, Change = $18.858 Total = $47.35, Change = $2.65
Exercise 7-101 a 2.4 b 6.2 c 4.16
d 4.1 e 14.65 f 2.1975g 0.008 h 2.6775 i 24.45j 3.675 k 0.518 75 l 0.106
2 a 2.4 b 1.13 c 5.75d 8.08 e 11.9 f 13.75g 14.75 h 259.45 i 0.122
3 a 0.217 b 4.625 c 0.013d 56.25 e 12.763 f 0.855g 0.6875 h 0.0083 i 13.01j 0.157 k 64.21 l 0.058
Exercise 7-111 a more, there are two 0.5s in every whole
c 362 a more c 683 The answer is more than the number.4 B5 a 5088 ÷ 12 b 1782 ÷ 11
c 3330 ÷ 45 d 17.25 ÷ 25e 12 920 ÷ 38 f 495 ÷ 15g 16 800 ÷ 75 h 1482.3 ÷ 61i 660 ÷ 22
6 a 8.7 b 36.6 c 4.9 d 7.4e 108 f 4.2 g 208 h 80
i 5.7 j 7.85 k 152 l 12.6m 3.4 n 1230 o 62
Mental skills 7B2 a 108 b 243 c 414 d 171
e 306 f 567 g 189 h 1354 a 187 b 242 c 418 d 440
e 275 f 209 g 594 h 3416 a 528 b 180 c 348 d 372
e 624 f 216 g 312 h 444
Exercise 7-12
2 a 0.4 b 0.375 c 0.75d 1 e 0.5 f 0.75g 0.6 h 0.25 i 0.625j 0.875 k 0.5 l 1
3 The fractions are equivalent, e.g. = =
4 a 4.8 b 23.75 c 12.625d 6.6 e 57.4 f 19.125g 110.875 h 80.25
5 a bc d 0.e f 0.g h 0.i 0. jk 0. l
m 0. no
6 7 a b 1.6
c de fg 0. hi 21.
1 FractionMeaning as
division Decimal
a 3 ÷ 5 0.6
b 1 ÷ 2 0.5
c 1 ÷ 4 0.25
d 4 ÷ 5 0.8
e 2 ÷ 5 0.4
f 3 ÷ 4 0.75
g 1 ÷ 5 0.2
h 1 ÷ 8 0.125
35---
12---
14---
45---
25---
34---
15---
18---
12--- 2
4--- 4
8---
0.1.
0.3.
0.16.
142857. .
0.6.
285 714. .
0.2.
428 571. .
571 428. .
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17 NCM7 2ed SB ANS.fm Page 529 Friday, June 6, 2008 11:19 PM
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530 NEW CENTURY MATHS 7
Exercise 7-131 a 0.4 b 0.5 c 0.8 d 0.7
e 2.6 f 0.3 g 0.9 h 2.92 a 0.48 b 0.74 c 0.07
d 0.29 e 0.31 f 0.66g 2.10 h 4.00
3 a 25.35 b 341.77 c 321.33d 734.65 e 27.76 f 1314.12
5 a 0.96 b 1.43 c 0.09 d 0.64e 0.85 f 1.67 g 1.33 h 1.71i 1.72 j 0.97 k 0.58 l 0.63
6 a 10.3337 b 431.5433 c 1.4450d 3217.6541 e 4.6709 f 0.8889
7 a 6 b 22 c 6 d 13 e 38 Teacher to check.
Exercise 7-141 $43.30 2 112.9 m3 $9 4 6 drink bottles5 15.8 km 6 26.6 km7 258.3 tonnes 8 3 whole shelves9 60.84 seconds
10 41.04, 0.829, 328.24, 4.7292, 2.517 0611 1.4 km12 a $15.24 b $6.84
c $487.76 d $1234.0513 400 sheets14 a
b 2.4 MHzc 0.8 MHz (Nova and The Edge or SBS
Radio 2)d 4.0 MHz (SBS Radio 2 and WS-FM)
4
QuestionCalculator
display
Rounded (1 decimal
place)
Rounded (2 decimal
places)
12.19 ÷ 3 4.06333 333 3 4.1 4.06
12.32 ÷ 6 2.053 333 333 2.1 2.05
19.82 ÷ 9 2.202 222 222 2.2 2.20
56.85 ÷ 11 5.168 181 818 5.2 5.17
17.13 ÷ 4 4.2825 4.3 4.28
12.65 ÷ 12 1.054 166 66 1.1 1.05
4.875 ÷ 21 0.232 142 857 0.2 0.23
27.45 ÷ 8 3.431 25 3.4 3.43
17 ÷ 12 1.416 666 667 1.4 1.42
254.678 ÷ 32 7.958 687 5 8.0 7.96
AB
C
The
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e
WS-
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BS
2DAY
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JM
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ER
90 110
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a
NO
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SBS
Rad
io
15 a i 14 February 1966ii Pounds, shillings and pence
iii It is easier to calculate in a system based on tens.
iv 1c, 2c, 5c, 10c, 20c, 50c coins; $1, $2, $5, $10, $20, $50 notes
v $1 and $2 coins, $100 note, 198416 Teacher to check.
Power plus1 a Queen’s chamber 8.07
armoury 8.262throne room 8.79banquet hall 9.24kitchen 9.96dungeon 8.16
2 a 0.0004 b 0.000 008 c 1.331d 0.2 e 0.6 f 0.3
3 a 3.7, 24.6 b 2.3, 5.7, 6c 5.1, 0.72, 4.5, 18
Chapter 7 revision1 a 40.36 b 520.703
c 0.012 d 8.0692 a 1.23 km b $20.00 c $4.60
d 0.15 h (or 1.5 h) e 140.0 kgf 4500.000 people g $50 850.00h $11.30 i 134.9c per L
3 a
b
4 a 340, 56.86, 50.141, 34.98, 34.89, 3.998, 3.099
b 8.6, 1.006, 0.86, 0.662, 0.652, 0.23, 0.136, 0.086
c 1.293, 1.239, 1.1015, 1.0155 a 0.4 b 0.13 c 0.07 d 0.111 e 0.045
6 a b c d e 4
7 a 65.355 b 104.49 c 11.965d 1037.9 e 396.51 f 228.155g 2.379 h 151.413
8 a 75.4 b 754 c 7540d 1.39 e 0.139 f 0.0139
9 a 319.2 b 31.92 c 319.2d 31 920 e 319.2 f 319 200
10 a 16.5 b 0.6 c 48.92d 7.32 e 9.2 f 670g 1.3325 h 0.001 i 5.137
11 $25.9512 a 381.2 b 12.2 c 0.6875 d 16.313 a 25 b 31.8 c 230 d 25.4
2.41.6 1.7 1.9 2.32.0 2.2
0.710.63 0.64 0.67 0.69
510------ 89
100--------- 9
100--------- 444
1000------------ 51
1000------------
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531ANSWERS
14 a 0.8 b 0.375 c d15 a 460 b 126 c 2345.88
d 3.9 e 79 000 f 678.4g 100 h 102.01
16 $340.20 17 $8.2518 38.8c per brick
Chapter 8
Start up1 a 230 b 450 c 97 d 4000
e 1032 f 94.5 g 400 h 270i 90 j 63 k 20 l 43m 65 n 37.5 o 9.5 p 8.2q 42.3 r 0.72 s 0.85 t 10.9
2 a 9.77 b 5.87 c 16.34 d 1.45e 30.02 f 4.49 g 7.15 h 7.83i 7.75 j 4.65
3 a tape measure, metresb ruler, centimetres or millimetresc ruler, millimetresd tape measure, centimetres or millimetrese tape measure, metresf measuring stick or tape, metresg trundle wheel, metresh tape measure, metresi tape measure, centimetres, millimetres or
metresj ruler, millimetresk stopwatch, seconds
4 a 35 mm b 55 mm c 28 mmd 60 mm e 50 mm f 10 mm
5 a 7 cm b 3.5 cm c 9.2 cmd 6.8 cm e 3.4 cm f 12 cm
6 a 32 cm b 36.9 mm c 93 m7 a 1000 m b 100 cm
c 1000 mm d 10 mm8 a 54 cm2 b 25 cm2 c 500 mm2
d 144 cm2 e 40 cm2 f 6 cm2 g 0.6 m2 h 225 mm2 i 48 cm2
Exercise 8-011 Teacher to check.3 a Time, minutes and seconds
b Temperature, °C c Distance, kilometresd Mass or volume, kilograms or cubic
centimetrese Time, hours and minutesf Distance, kilometresg Time, hours and minutesh Speed, kilometres per hour
0.5.
6.6.
i Capacity, millilitresj Area, square metres or hectares
4 a Mass, kilograms or length, centimetresb Speed, kilometres per hour or knotsc Height, metres or centimetresd Temperature, °C e Capacity, number of people
5 Teacher to check.
Exercise 8-021 a 200 cm b 1500 cm c 50 cm
d 350 cm e 25 cm f 125 cmg 1548 cm h 1260 cmi 300 000 cm j 2 500 000 cmk 1 250 000 cm l 2 025 000 cmm 42 cm n 6.5 cmo 0.7 cm p 12.5 cm
2 a 30 mm b 8000 mmc 400 mm d 25 000 mme 115 mm f 4200 mmg 32.5 mm h 15 750 mmi 5 000 000 mm j 12 000 000 mmk 8 400 000 mm l 32 750 000 mmm 780 mm n 2000 mmo 1250 mm p 700 mm
3 a 2 m b 3 m c 8.5 md 9.8 m e 12.5 m f 2.75 mg 0.8 m h 0.25 m i 0.75 mj 0.325 m k 6000 m l 18 000 mm 23 600 m n 48 250 m o 13.8 mp 800 m
4 a 2 km b 1.385 km c 1.4 kmd 2.9387 km e 0.375 km f 0.098 kmg 0.235 km h 0.0648 km i 0.5 kmj 2.7 km k 3.2 km l 6.07 km
5 a 1200 cm b 2800 cm c 20 md 24 km e 1.5 km f 0.65 kmg 2.3 km h 6 m i 250 cmj 0.2 km
6 a 200 cm, 2500 mm, 3 mb 240 cm, 3200 mm, 4 mc 700 mm, 0.8 m, 900 cmd 0.045 km, 4800 cm, 450 me 60 cm, 650 mm, 0.69 mf 1500 cm, 150 m, 1.5 kmg 0.18 m, 1750 mm, 180 cmh 0.011 m, 120 cm, 1.3 m
7 D8 a pencil 120 mm, screen 330 mm, door
800 mm, ruler 35 mm, room 7400 mmb pencil 0.12 m, screen 0.33 m, door 0.8 m,
ruler 0.035 m, room 7.4 mc Teacher to check.
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532 NEW CENTURY MATHS 7
9 a kilo b centi c milli10 Teacher to check.
Exercise 8-031 a 40°C b 75°C c 37.6°C
d 37.4°C e 37.75°C2 a 166 mm b 97 mm c 120 mm
d 117 mm e 26 mm f 75 mmg 47 mm h 170 mm i 163 mmj 193 mm
3 a 13 cm b 8 cm c 19 cmd 13 cm e 9 cm f 10 cmg 12 cm h 25 cm i 21 cmj 11 cm
4 a C is 4.4, K is 4.7, S is 6.15b C is 27°C, K is 14°C, S is 5°Cc C is 18 125, K is 3750, S is 9375
5 a b 143 cm c 96 km/h
d 0.95 V e 85 mL6 Teacher to check. 7 A8 Teacher to check.
Mental skills 81 a 730 b 8.4 c 24 d 591
e 0.06 f 4500 g 180 h 0.75i 24 j 12 000 k 520 l 7m 48 n 8650
2 a 2200 b 0.8 c 2.35 d 0.36e 330 f 4.9 g 0.27 h 48i 10 800 j 16 900 k 365 l 7.4m 3 n 0.065 o 960 p 740 000
Exercise 8-041 a i 1 mm ii ±0.5 mm
b i 1°C ii ±0.5°Cc i 1 min ii ±0.5 mind i 100 g ii ±50 ge i 1 cm ii ±0.5 cmf i 1° ii ±0.5° g i 5 km/h ii ±2.5 km/hh i 250 g ii ±125 gi i 50 mL ii ±25 mLj i 1 kL ii ±0.5 kLk i of a tank ii ± of a tank
2 D
Exercise 8-05Teacher to check.
Exercise 8-061 a 46 mm b 44 cm c 118 m
d 39 cm e 246 cm f 2000 mm
78---
14--- 1
8---
g 31.8 km h 26 cm i 208 mmj 60 mm k 48 m
2 a 90 mm b 178 mmc 126 mm d 116 mm
3 a 44 m b 30 cm c 48 mmd 40 m e 36 km f 54 mm
4 a 4 cm b 8 cm c 14 cmd 18 cm e 9.5 cm f 7.5 cm
5 Any two numbers that add up to 156 C
Exercise 8-071 a Some possible shapes:
b Some possible shapes:
2 C3 Some possible shapes:
4 a 10 cm2 b 8 cm2 c 10 cm2
d 12.5 cm2 e 4 cm2 f 4 cm2
g 6.5 cm2 h 28 cm2 i 15 cm2 5 a 5 cm2 b 8 cm2 c 9 cm2
d 6 cm2 e 9 cm2 f 5 cm2 g 10 cm2 h 10 cm2
Exercise 8-081 a 1500 mm2 b 1.5 m2
c 6.9 cm2 d 65 000 cm2 e 500 000 mm2 f 1.22 m2 g 12.5 cm2 h 790 mm2 i 750 000 mm2 j 86.5 m2 k 0.69 m2 l 4700 cm2
2 a 102 400 mm2 b 0.1024 m2 3 25 m2, 250 000 cm2, 25 000 000 mm2 4 10 800 mm2, 108 cm2, 0.0108 m2
a
b
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533ANSWERS
5 a 625 mm2, 6.25 cm2
b 1100 mm2, 11 cm2 c 1050 mm2, 10.5 cm2 d 2250 mm2, 22.5 cm2
Exercise 8-091 a 55.8 m2 b 58.6 m2 c 96 cm2
d 324 m2 e 1.44 cm2 f 4 cm2 g 96 mm2 h 225 m2 i 154 mm2 j 1890 cm2 k 448 m2
2 a 15 cm2 b 16 cm2 c 36 mm2 d 18 cm2 e 10 cm2 f 48.59 m2 g 8.82 m2 h 9.01 mm2 i 7.68 cm2 j 45.72 cm2 k 21.76 m2 l 1750 mm2
3 a 17 500 mm2 b 15.6 m2 c 300 mm2
d 48 cm2 e 7.8 m2
4 D 5 C
Exercise 8-101 a 152 cm2 b 372 cm2 c 60 cm2
d 11 cm2 2 a 11 250 cm2 b 500 cm2 c 1300 cm2 3 a 140 cm2 b 67.5 km2 c 48 mm2
d 220 m2 e 150 cm2 4 a 30 cm2 b 100 cm2 c 204 mm2
d 135 cm2 e 55 cm2 f 22 m2 g 128 mm2 h 372 cm2
5 422.5 m2 6 a i 20 m2 ii 20 m2 iii 12.8 m2
b 80 tiles c 3.6 L7 42.8 m2 8 60 m2 9 D
Exercise 8-111 a 245 ha b 3445.2 ha
c 1 275 020 ha d 0.15 hae 0.0854 ha f 0.2 ha
2 a 2.45 km2 b 34.452 km2 c 12 750.2 km2
3 a i 12 km2 ii 1200 hab i 40 000 m2 ii 4 hac i 64 km2 ii 6400 had i 7200 m2 ii 0.72 hae i 9600 m2 ii 0.96 haf i 16 km2 ii 1600 ha
4 3 002 800 ha 5 1348.05 km2 6 a 0.875 km2 b 87.5 ha7 a 10 m b 20 m c 25 m
d 5 m e 8 m f 2 m8 a 10 000 m b 6250 m c 4000 m
d 2000 m e 12 500 m f 500 m9 About 6.2. 10 About 186 times.
11 About 32 ‘Italys’. 12 About .
13 14 C
Power plus1 a P = 47 cm A = 82.5 cm2
b P = 46 cm A = 52.5 m2 c P = 79 cm A = 206.5 cm2 d P = 277 mm A = 2250 mm2
2 a and b Teacher to check.c 15cm × 15 cm
3 a Teacher to check. b 6 cm × 6 cm4 a 66 m2 b 11 L c 3, $137.85 d 15 m2
Chapter 8 revision1 a time: seconds b time: hours
c rainfall: millimetres c temperature: °C2 Teacher to check.3 a 300 cm b 8000 mm
c 3 000 000 km d 6.5 km e 75 cmf 25 mm g 7.8 m h 5.2 m
4 B 5 1.66 a 16°C b 1°C c ±0.5°C7 a 152 mm, 15.2 cm b 151 mm, 15.1 cm
c 134 mm, 13.4 cm8 a 52 m b 36 mm c 64 cm d 88 mm9 a 45 m b 122 m c 45.2 m
d 38 m e 70 m10 a 6 cm2 b 9 cm2 c 7 cm2
11 a 91 000 cm2 b 250 mm2 c 40 000 m2 d 1 000 000 m2 e 3.8 m2 f 8 600 000 mm2 g 2.4 cm2 h 17.5 m2
12 a 16 m2 b 24 cm2 c 360 mm2 d 112 mm2 e 5.2 cm2 f 187 km2 g 162 m2
13 a 9 cm2 b 34 m2 c 84 m2 d 12.5 mm2 e 196 m2 f 128.2 mm2
14 6 L15 a 3910 km2 b About 113 c 6 800 000 ha
Chapter 9Start up
1 Teacher to check.2
3 a AB and DC, or AD and BC b AC and BD c No d 90° e 65°
4 a equilateral b rectangle
13---
180------
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534 NEW CENTURY MATHS 7
5
6 a 2 b 2 d 6 e 27 a T b T c F d F8 Teacher to check
Exercise 9-011 a EH and EI b EH ⊥ EI c DF II GJ 2 a and b
c They are vertically opposite angles.3
4 EF, the line, is infinite. The interval EF is the section of the line between point E and point F.
5 a ΔPQT, ΔPRS b i PQ ii TS c TQ II SRd and e
f Corresponding angles on parallel lines are equal.
6 a, c, d, and e b FE
7 a, b and d Teacher to check. c side g8 a and b
a b c
d e f
g h
Infinite
P
Q
R
S T
LM
K
lm
k
P
Q
R
S
T
F
E
D
C
A B
C D
E
F
c True9 a False b False
c True d ST and VT 10 a Teacher to check. b Y
c WX II ZY or WZ II XY d WX ⊥ XY, XY ⊥ YZ, YZ ⊥ ZW,
or ZW ⊥ WX e i Side WX is perpendicular to side XY.
ii The length of side WX is equal to thelength of side XY.
Exercise 9-021 a square b triangle c pentagon
d kite e rectangle f parallelogramg trapezium h hexagon, non-convexi quadrilateral j equilateral trianglek pentagon l hexagon
2 a 6 b 4 c 9 d 10 e 7f 5 g 12 h 8 i 11
3 a, j, k, l 4 D5 Teacher to check.6 b, e, f 7 Teacher to check.8 a 2 b 5 c 99 a square, triangle b 2 rectangles
c rectangle, trapezium, and pentagond rectangle and two trapeziumse rectangle, trianglef two triangles and two trapeziums(Other answers possible.)
10
Exercise 9-03
1 Acute Obtuse Right Equilat. Isosc. Scal.
c a b g d a
f d i j e b
g e f c
h l h l
j i
k k
a b c
d e f
g
(Other answers possible.)
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535ANSWERS
2, 3 Teacher to check. 4 No. In an equilateral triangle, all angles are
equal.5
6 Yes, any equilateral triangle.7 No, two obtuse angles can’t be joined to form
a triangle.8 C 9 Teacher to check.
Mental skills 92 a 720 b 486 c 825 d 128
e 560 f 216 g 189 h 432i 560 j 616 k 135 l 675
Exercise 9-041, 2 Teacher to check.3 a i ∠Q, ∠R, SR, QS ii ∠S, QR
b i ∠N, OM ii ∠O, MN c i ∠D, EC ii ∠E, CD d i All angles and all sides are equal.e i ∠M, KL ii ∠K, ∠L, ML, KM f i ∠X, YZ ii ∠Y, XZ
4 opposite, opposite, smallest5 a d b They are the same, all equal 60°.6 d equal, equal, 60 7 Teacher to check8 a b b Two angles are equal9 d equal, equal
10 b 7 + 5 � 15 so the triangle inequality rule does not hold.
11 Shape Properties
Equilateral triangle
• All three sides are equal• All three angles measure 60°• Has three axes of symmetry
Isosceles triangle
• Two sides are equal• Two angles equal (opposite
the equal sides)• Has one axis of symmetry
Scalene triangle
• No sides or angles equal• Has no axes of symmetry
a b
c d
None
e f
None
Exercise 9-051 Teacher to check.2 a convex b convex
c non-convex d convexe non-convex f non-convex
3 a rhombus b parallelogramc square d trapeziume rectangle f kite
4 Teacher to check.5 a
(Note: An isosceles trapezium has line symmetry, but other trapeziums do not.)
d Pairs of adjacent sides equal, diagonals intersect at right angles. (Other answers possible.)
6
7 a 2 b 4 c 2 d 2
Trap
eziu
m
Par
alle
log
ram
Rh
om
bus
Rec
tan
gle
Sq
uar
e
Kit
e
Opposite sides are equal ✔ ✔ ✔ ✔
Opposite sides are parallel ✔ ✔ ✔ ✔
Opposite angles are equal ✔ ✔ ✔ ✔
All angles are 90° ✔ ✔
Diagonals are equal ✔ ✔
No. of axes of symmetry 0 0 2 2 4 1
Order of rotational symmetry 0 2 2 2 4 0
8
Trap
eziu
m
Par
alle
log
ram
Rh
om
bus
Rec
tan
gle
Sq
uar
e
Kit
e
Diagonals are equal ✔ ✔
Diagonals bisect each other ✔ ✔ ✔ ✔
Diagonals intersect at right angles ✔ ✔ ✔
Diagonals bisect the angles of the quadrilateral
✔ ✔
a b
c d
e fNone
None
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67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
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78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
536 NEW CENTURY MATHS 7
9 B10 a rectangle, square b square, rhombus
c parallelogram, rectangle, square, rhombusd parallelogram, rhombus, rectangle, squaree rectangle, squaref parallelogram, rectangle, square, rhombusg parallelogram h rhombus, square
11 a Yes, a square is a rectangleb Yes, a rhombus is a parallelogram.
Exercise 9-061 a 60°–30° b 45°
c 45° d 60°–30° 2 Teacher to check. 3 Teacher to check.4 Teacher to check. 5 Teacher to check.6 d isosceles
12 Shape Properties
Trapezium • One pair of parallel sides• No axes of symmetry
Kite • Two pairs of adjacent sides are equal
• One pair of opposite angles equal
• Has one axis of symmetry• Diagonals intersect at right
angles
Parallelogram • Opposite sides are equal and parallel
• Opposite angles are equal• No axes of symmetry• Diagonals bisect each other
Rhombus • All four sides are equal• Opposite sides are parallel• Opposite angles are equal• Has two axes of symmetry• Diagonals bisect at right
angles• Diagonals bisect the angles of
the rhombus
Rectangle • All four angles measure 90°• Opposite sides are equal and
parallel• Has two axes of symmetry• Diagonals are equal• Diagonals bisect each other
Square • All four sides are equal. • All four angles measure 90°• Has four axes of symmetry• Diagonals are equal and
bisect each other at right angles
• Diagonals bisect the angles of the square
7 Teacher to check.8 c They are the same.9 trapezium 10 kite
11 Perpendicular lines intersect to form a right angle. A vertical line is perpendicular to the horizontal.
Exercise 9-071 Teacher to check. 2 Teacher to check.3 Teacher to check. 4 Teacher to check.5 b parallelogram d Yes6 b rhombus7 a PS and QR
c ∠P = ∠Q = 104°, ∠R = ∠S = 76°d ∠P = ∠Q, ∠S = ∠R
8 Teacher to check.9 b trapezium 10 Teacher to check.
11 Teacher to check. 12 Teacher to check.
Power plus1 a pentagon, non-convex
b hexagon, non-convexc dodecagon, non-convexd octagon, non-convexe quadrilateral, non-convexf heptagon, non-convex
2 Teacher to check.3 a Yes b No c Yes
d Yes e No f No4 a Angles of 90° b All sides equal
c All sides equal5 a 2 b 20 c 546 a square, rhombus
b square, rectangle, rhombus, parallelogramc kite, rhombus, squared square, rectanglee square, rhombus f square, rectangle
7 Teacher to check.8 a parallelogram b kite
c rectangle d rectanglee parallelogram f parallelogram
9 Teacher to check. 10 Teacher to check.11 c rhombus12 b square
Chapter 9 revision1 a AD and BC
b AD and DC, BC and DC c ∠ADC or ∠CDA and ∠BCD or ∠DCB
2 decagon3 circle, ellipse, etc.
17 NCM7 2ed SB ANS.fm Page 536 Friday, June 6, 2008 11:19 PM
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
537ANSWERS
4 Teacher to check.5 a equilateral, acute-angled
b scalene, right-angledc isosceles, acute-angledd scalene, obtuse-anglede scalene, acute-angledf isosceles, right-angled
6 a isosceles, acute-angledb ∠ F and ∠ H
7 Teacher to check.8 b The longest side is opposite the largest
angle.9 a square b rhombus
c trapezium d parallelograme rectangle f kite
10 a Teacher to check.b a4, b2, d2, e2
11 A quadrilateral with all sides equal.12 Teacher to check.13 a equilateral triangle
b parallelogram, rectangle, rhombus or square
c pentagond rectangle, parallelogram, rhombus or
squaree trapeziumf scalene acute-angled triangle
14 Teacher to check. 15 Teacher to check.16 Teacher to check.
Mixed revision 31
2 a 9.44 b 3.1 c 9.05d 21.89 e 5.407 f 5.283
3 a 4.34 b 10.023 c 83.6d 2.105 e 0.02 f 13.44
4 $3.205 a 0.2 b 0.375 c 0.6 a 0.8 b 12.06 c $9.80 d 3.807 8.7°C 8 0.25 m9 a km b mm or cm c m2
d m e cm2 or mm2 10 a 200 cm b 120 mm
c 37.5 cm d 1.25 km11 a 84 kg b 1 kg c ±0.5 kg12 a 24 mm b 160 cm
c 30 cm d 56 cm 13 101.6 cm14 a 30 000 cm2 b 950 mm2
c 6.2 m2 d 7.4 cm2
3
2.25
21
0.5
0
2.90.75 1.3 1.6
5.
15 a 32 mm2 b 1600 cm2 c 0 cm2 d 121 cm2
16 side is 8 cm, P = 32 cm17 4 cm18 a trapezium b pentagon
c octagon d equilateral trianglee kite f scalene triangleg parallelogram h hexagoni right-angled triangle j isosceles trianglek square l rhombus
19 a isosceles triangle b rhombus or squarec rectangle d scalene trianglee decagon
20 Teacher to check.
Chapter 10Start up
1
2 a b c or 0 d = 1
3 a b = c
d = e = f
g = h = =
4 a b = c
d = e = f
g = h = =
5 a b c d =
6 a = b c = d
7 a = b = c =
d = e f =
g = h = = =
8
(Other answers possible.)d Teacher to check.
9 a 12 b 16 c 4 d 7e 11 f 5 g 2 h 7i 5 j 12 k 7 l 10
10 a 1, 3, 5, 15b 1, 2, 4, 5, 10, 20c 1, 2, 3, 4, 6, 9, 12, 18, 36
11 a 3, 6, 9, 12, 15b 6, 12, 18, 24, 30c 10, 20, 30, 40, 50
15---
2643------ 17
43------ 0
43------ 43
43------
14--- 3
6--- 1
2--- 7
12------
1520------ 3
4--- 6
9--- 2
3--- 5
9---
2136------ 7
12------ 6
12------ 3
6--- 1
2---
34--- 3
6--- 1
2--- 5
12------
520------ 1
4--- 3
9--- 1
3--- 4
9---
1536------ 5
12------ 6
12------ 3
6--- 1
2---
1231------ 1
3--- 1
2--- 8
10------ 4
5---
420------ 1
5--- 13
20------ 15
20------ 3
4--- 5
13------
3060------ 1
2--- 20
60------ 1
3--- 45
60------ 3
4---
1060------ 1
6--- 13
60------ 25
60------ 5
12------
3960------ 13
20------ 48
60------ 24
30------ 12
15------ 4
5---
a b c
17 NCM7 2ed SB ANS.fm Page 537 Friday, June 6, 2008 11:19 PM
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8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
538 NEW CENTURY MATHS 7
Exercise 10-01
2 a 2 b 3 or 3 c 1
d 2 or 2 e 3 or 3
3
4 a b c d
e f g h
i j k l
5 a 4 b 3 c 1 d 4
e 1 f 4 g 6 h 7
i 5 j 10 k 3 l 10
Exercise 10-021 a 2 b 10 c 16 d 8
e 4 f 6 g 5 h 5i 4 j 8 k 6 l 5
2 a 15 b 42 c 12 d 30e 40 f 20 g 10 h 8i 18 j 21 k 12 l 60
3 A
1 Proper fractions
Improper fractions
Mixed numerals
1
3
20
4
3100--------- 100
45--------- 1
2---
23--- 3
2--- 2
5---
150250--------- 87
86------ 1
4---
8687------ 25
1------ 1
20------
35--- 1000
250------------
312------ 301
300---------
13--- 4
6--- 2
3--- 3
4---
24--- 1
2--- 6
12------ 1
2---
a
c
d
e
f
b
+
+
+ +
+ +
+
+
+ +
32--- 13
8------ 9
7--- 10
3------
92--- 37
10------ 37
6------ 23
12------
385
------ 14215
--------- 12611
--------- 557
------
13--- 1
4--- 3
10------ 1
5---
335------ 3
8--- 5
6--- 1
5---
37--- 10
11------ 15
19------ 1
10------
Exercise 10-031 Teacher to check.2
3 a = = = = = =
b = = = = = =
c = = = = = =
d = = = = = =
e = = = = = =
f = = = = = =
4 D
5 a b c d e
f g h i j
k l m n o
6 Teacher to check.
7 a = b = c ≠
d ≠ e = f ≠
g ≠ h ≠
Exercise 10-041 a C b D c C
2 a b c d e
f g h i j
3 a 1 b 1 c 2 d 1 e 2
f 2 g 1 h 1 i 1 j 2
4 a 1 b 3 c 4 d 6
a
15---
525------
420------ 6
30------
315------ 2
10------
5
2
4
3
6
b
58---
1524------
3556------
2032------
1016------
4572------
4064------ 3
78
9 42
14--- 2
8--- 3
12------ 4
16------ 5
20------ 6
24------ 7
28------
56--- 10
12------ 15
18------ 25
30------ 30
36------ 60
72------ 100
120---------
23--- 4
6--- 6
9--- 8
12------ 10
15------ 20
30------ 200
300---------
710------ 14
20------ 21
30------ 35
50------ 56
80------ 70
100--------- 105
150---------
78--- 14
16------ 21
24------ 35
40------ 63
72------ 77
88------ 350
400---------
34--- 6
8--- 9
12------ 15
20------ 24
32------ 36
48------ 75
100---------
2136------ 3
8--- 28
35------ 12
20------ 6
15------
23--- 4
12------ 1
2--- 3
5--- 49
56------
1628------ 7
10------ 45
54------ 1
4--- 13
20------
12--- 10
20------ 1
3--- 4
12------ 1
4--- 4
12------
34--- 5
7--- 14
21------ 2
3--- 6
12------ 7
13------
59--- 4
7--- 3
12------ 9
35------
38--- 1
4--- 4
5--- 3
4--- 7
13------
37--- 4
5--- 1
4--- 2
3--- 4
15------
13--- 1
3--- 2
3--- 1
2---
13--- 1
4--- 1
2--- 6
7--- 1
10------
12--- 1
6--- 1
4--- 3
4---
17 NCM7 2ed SB ANS.fm Page 538 Friday, June 6, 2008 11:19 PM
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
539ANSWERS
e 100 f 17 g 100 h 1
i 5 j 15
5 D
Exercise 10-051 a b c d e f
2 a � b � c �
d � e � f �
g � h � i �
j � k � l �
m � n � o �
p � q 3 � 3 r 2 � 2
s 1 � 1 t 2 � 2
3 C
4 a b
c d
e 0.5, 0.9 f 0.7
5 a b
c 1, d 3, 1
6 a
b
c
d
e
7 a
b
c
d
e
f
23--- 7
20------ 11
16------ 27
50------
13--- 4
5---
310------ 2
3--- 3
6--- 3
4--- 3
5--- 3
5---
12--- 1
3--- 2
3--- 3
4--- 3
8--- 1
2---
78--- 3
4--- 1
4--- 1
3--- 3
5--- 7
10------
56--- 1
2--- 1
6--- 1
4--- 5
12------ 1
3---
17100--------- 2
5--- 7
10------ 4
5--- 17
20------ 6
10------
1115------ 2
3--- 1
3--- 2
5--- 63
100--------- 4
5---
25--- 3
7--- 3
4--- 5
8--- 3
7--- 2
5---
57--- 2
5--- 1
3--- 2
5---
110------, 1
7---, 1
5---, 1
4---, 1
3---, 1
2--- 2
5---, 3
7---, 3
5---, 5
7---
18---, 1
2---, 8
9--- 2
9---, 3
10------, 3
8---, 2
5---, 4
7---, 3
5---
27---, 4
5---, 1
2---, 3
5---, 2
3---,
67---, 6
8---, 6
9--- 5
4---, 5
6---, 5
9---
45---, 2
3---, 1
2---, 2
5--- 12
5------, 1
5---, 40
50------, 3
4---
0 1 214--- 3
4--- 1
4---21
2---1
10 235---2
5--- 1
5---1 3
5---1 4
5---1
10 16--- 1
3--- 5
12------ 3
4---
10 2660------ 12
60------ 40
60------ 55
60------
110------ 1
5--- 2
3--- 11
12------ 1
2---1 3
4---1
3060------1 45
60------1
10 580------ 30
80------ 45
80------ 60
80------ 70
80------
116------ 3
8--- 9
16------ 3
4--- 7
8---
210 23--- 1
3---1 7
3---
33---
20 1
55---
15--- 3
5--- 3
5---1 9
5--- 2
5---2
20 114--- 3
4--- 1
4---1 7
4--- 3
4---2
10 13--- 1
2--- 5
6--- 1
6---1
20 114--- 3
8--- 5
8--- 7
8--- 11
8------ 3
4---1
0 112---2
5--- 7
10------ 9
10------1
4---
Exercise 10-061 a 1 b = c = 1 d = 1
e f = 1 g h =
i = 1 j 0 k = 3 l = 1
2 a b c d e 1
f g h i j
k l 1 m 0 n 1 o
p q 1 r s 1 t 1
u v w x 0 y
3 4 5
6 of an hour 7 8 =
9 a 4 b c 4 d 5 = 5
e 3 f 6 g 2 h 6
i 10 j 8 = 8 k 6 l10 D
Exercise 10-071 C2 a 3 b 4 c 3 d 3
e 4 f 4 g 2 h 3
i 2 j 4 k 2 l 5
m 1 n 1 o 4 p 12
3 a 3 b 1 c 6 d 5
e 5 f 5 g 2 h 4
i 6 j 3 k 4 l 2
4 a 2 b 1 c d 3
e 1 f 2 g 1 h
i 1 j 1 k l 1
m 1 n 2 o 1 p
Exercise 10-081 a 5 b 4 c 8 d 6 e 5 f 18
g 3 h 18 i 15 j 500 k 750 l 262 a $1 b $8 c $20
d 20c e $0.30 f $30g $45 h 36c i $2.50j $2.25 k $200 l $780
3 a 30 minutes b 90 minutesc 9 hours d 18 minutese 73 days f 45 secondsg 200 seconds h 216 seconds
610------ 3
5--- 3
3--- 4
3--- 1
3---
25--- 4
4--- 3
10------ 4
12------ 1
3---
86--- 1
3--- 21
6------ 1
2--- 9
8--- 1
8---
56--- 13
15------ 1
4--- 1
18------ 5
24------
120------ 20
63------ 23
60------ 43
45------ 3
10------
2645------ 5
24------ 11
20------ 7
24------
1121------ 3
14------ 9
20------ 3
20------ 7
24------
1324------ 1
24------ 7
12------ 19
60------
1112------ 1
6--- 13
16------
56--- 8
10------ 105
200--------- 21
40------
12--- 2
3--- 2
4--- 1
2---
25--- 3
8--- 2
3---
48--- 1
2--- 5
7--- 3
5---
14--- 2
15------ 1
8---
112------ 1
10------ 1
2--- 5
6---
18--- 3
20------ 1
12------ 10
21------
110------ 3
8--- 7
8--- 13
60------
34--- 1
4--- 1
2--- 1
4---
45--- 2
5--- 3
8--- 4
15------
115------ 11
20------ 1
4--- 19
40------
12--- 2
5--- 3
7--- 1
3---
34--- 7
12------ 7
10------ 3
4---
2140------ 19
20------ 5
6--- 7
10------
12--- 4
5--- 11
12------ 3
4---
17 NCM7 2ed SB ANS.fm Page 539 Friday, June 6, 2008 11:19 PM
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67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
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012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
540 NEW CENTURY MATHS 7
i 32 hours j 24 minutesk 18 hours l 336 secondsm 8 months n 35 minutes
4 a 250 m b 1500 m c 625 md 1600 m e 300 m f 3500 mg 8 cm h 4 mm i 27 mmj 4.5 cm k 51 mm l 15 cmm 45 mm n 40 km o 35 m
5 D
Mental skills 102 a 9 b 8 c 7 d 8 e 3
f 56 g 14 h 30 i 33 j 28k 15 l 14 m 26 n 6 o 105p 60 q 28 r 11 s 163 t 39u 2
Exercise 10-091 d
2 a b c d e
f g h i j
3 a b c d e
f g h i j 1
k 2 l m n o
p 1 q 1 r s 6 t 15
4 a b 1 c 2 d 6 e 2
f 2 g 5 h 9 i 6
5 a + + b +
= 3 × = 2 ×
= = = 1
c + + + + d 5 × =
= 5 ×
= = 1
e 7 × = f 8 × =
= 1 = 4
6 a 3 b 15 c 5 d 2 e 13
f 22 g 4 h 19 i j 7
7 4 8 27 female, 18 male9 2 10 270
11 7A: 18 boys, 6 girls 7B: 15 boys, 5 girls7C: 21 boys, 7 girls 7D: 12 boys, 4 girls
112------
215------ 9
20------ 35
48------ 9
80------ 5
16------
964------ 20
63------ 21
160--------- 4
15------ 1
5---
17--- 2
7--- 1
18------ 1
6--- 7
12------
421------ 3
20------ 1
4--- 3
25------ 3
25------
27--- 1
10------ 11
24------ 2
5--- 3
5---
45--- 3
10------ 2
5---
12--- 1
3--- 7
9---
15--- 3
7---
14--- 1
4--- 1
4--- 3
5--- 3
5---
14--- 3
5---
34--- 6
5--- 1
5---
38--- 3
8--- 3
8--- 3
8--- 3
8--- 1
7--- 5
7---
38---
158
------ 78---
320------ 21
20------ 3
5--- 24
5------
110------ 4
5---
35--- 1
3--- 1
3---
12--- 9
10------ 1
5--- 1
4--- 1
2---
12 kg = g = 0.015 g
13 a b c d
e f g
14 127 stones
15 8 eggs, 20 cups of flour, 2 cups of sugar16 280 17 D
Exercise 10-101 3 2 53 a 6 b 12 c 184 a 20 b 405 a 12 b 15 c 21 d 15
e 35 f 40 g 16 h 4i 32 j 3 k 8 l 10
6 a b 4 c 1 d 1 e
f g h i 2 j
k l 2 m 3 n 15 o 14
p q 1 r s t 1
u 1 v 1 w x
7 a b c d
e f g h
i j k l
8 a 3 b 2 c d 1
e f 1 g 10 h
i 3 j 3 k 3 l 1
9 17 10 20
11 96 12 8
13 38 h or 38 h 24 min 14 B
Exercise 10-111 a 9% b 17% c 36% d 49%
e 22% f 30% g 20% h 75%i 25% j 48% k 20% l 82%
2 a 62 % b 33 % c 66 % d 6 %
e 16 % f 22 % g 55% h 90%
3 a 150% b 325% c 333 %
d 575% e 940% f 757 %
g 137 % h 177 %
4 a b c d e 1
f g h i j
5 A
3200 000-------------------- 3
200---------
78--- 7
10------ 3
7--- 7
30------
17--- 1
3--- 4
5---
12---
38--- 1
2--- 11
14------ 6
7---
2425------ 2
3--- 1
2--- 1
2---
25--- 1
2--- 3
4---
56--- 1
4--- 20
21------ 5
36------
23--- 1
6--- 27
28------ 9
10------
17--- 5
49------ 1
12------ 7
40------
14--- 2
9--- 2
15------ 1
6---
110------ 1
10------ 1
15------ 5
12------
34--- 4
5--- 7
8--- 1
3---
34--- 1
3--- 15
16------
13--- 1
8--- 1
9--- 1
2---
13---
25---
12--- 1
3--- 2
3--- 1
4---
23--- 2
9---
13---
17---
12--- 7
9---
120------ 7
50------ 2
25------ 9
10------ 1
25------
7200--------- 31
300--------- 25
400--------- 1
8--- 91
150---------
17 NCM7 2ed SB ANS.fm Page 540 Friday, June 6, 2008 11:19 PM
Page 44
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2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
541ANSWERS
Exercise 10-121 a 0.28 b 0.06 c 0.161 d 0.213
e 0.1204 f 0.1911 g 0.7807 h 0.265i 0.4525 j 0.02
2 a 24% b 50% c 86% d 57%e 6% f 55% g 38% h 3%i 27% j 0.1% k 31.5% l 2.6%m 87.5% n 5% o 0.3%
3 a 240% b 150% c 361%d 857% e 760% f 102%g 1250% h 900.1% i 2220%j 5001%
Exercise 10-13
3 Teacher to check.
Exercise 10-141 a 6 b 60 c 7.5 d 165
e 4.2 f 3.6 g 196 h 204
1 Fraction Decimal Percentage
a 0.25 25%
b 0.4 40%
c 0.33 33%
d 0.35 35%
e 1 1.4 140%
f 1 1.75 175%
2 Fraction Decimal Percentage
a 0.7 70%
b 0.6 60%
c 0.3 30%
d 0.84 84%
e 0.5 50%
f 0.125 12 %
g 0.38 38%
h 0.625 62 %
i 0.73 73%
j 0. 33 %
k 0. 66 %
l 0.99 99%
3.
14---
25---
33100---------
720------
25---
34---
710------
35---
310------
2125------
12---
18--- 1
2---
1950------
58--- 1
2---
73100---------
13--- 3
. 13---
23--- 6
. 23---
99100---------
2 a 105 mm b 148 kg c 7.2 gd $1.30 e 42 f $405g $15.40 h 3.6 ha i 6 min
3 B 4 42 marks5 260 girls 6 124 chickens7 147 plants 8 D
Power plus1
2 a b c d e
f g h i j
3 a 75 m b 45 m4 16 5 Teacher to check.6 Teacher to check. 7 7 eggs
8 a 7 b 2 c 1
d 4 e f 1
Chapter 10 revision1 a b c d
e f g h
2 a 1 b 1 c 3 d 7
e 5 f 8 g 1 = 1 h 10
3 a 300 b = cd classical e male vocal, rock groups
4 a 2 b 5 c 165 a 24 b 12 c 60
6 a = b = c =
d = e = f =
7 a b c d e f
8 =
9 a b
c 1 d 2 3
10 a 1 b = 1 c 7
d e f 5
g h i =
11
12 a 9 b 4 c
d 4 e 1 f 3
13 6 litres
14 a A 9, B 8, R 12, O 7, T 20, H 3
b 3 7, 8, 9, 12, 20; H O B A R T
13---
425------ 1
9--- 1
4--- 4
9--- 9
16------
23--- 5
7--- 9
10------ 3
4--- 3
4---
724------ 5
6---
58--- 5
8--- 2
47------
74--- 13
9------ 9
4--- 22
7------
5410------ 29
8------ 38
5------ 72
7------
34--- 1
11------ 2
7--- 1
5---
58--- 2
3--- 12
24------ 1
2--- 1
12------
100300--------- 1
3--- 17
300---------
13--- 2
6--- 3
4--- 12
16------ 4
5--- 16
20------
512------ 15
36------ 1
2--- 25
50------ 3
20------ 15
100---------
56--- 3
4--- 3
4--- 4
3--- 1
2--- 4
7---
826------ 4
13------
310------, 2
5---, 7
10------, 4
5--- 1
3---, 1
2---, 7
12------, 11
12------
38---, 7
8---, 1
4---, 7
4--- 3
5---, 5
8---, 8
12------, 8
5---, 1
4---,
106
------ 23--- 3
7---
710------ 5
6--- 9
20------
18--- 11
20------ 25
30------ 5
6---
49---
23--- 1
3--- 5
6---
310------ 1
3--- 2
3---
712------
12---
12---,
17 NCM7 2ed SB ANS.fm Page 541 Friday, June 6, 2008 11:19 PM
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56789012 9012345678890123456789012345678 1234512345678901234567890123 45678901234
345678901234567845678901234567890123456789012234567890123012
8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
542 NEW CENTURY MATHS 7
15 a 18 b 4 c 5d 12 e 6 f 8g 16 hours h 1600 mi 2 hours or 135 mins j 105 mmk 50 seconds l 125 cm
16 1 spotted 17
18 a b 6 c d e f
g 2 h 8 i 2 j 3 k 3 l
19 a 50 b c 1 d 2 e 6
f g 3 h 2 i 1
20 1521 a 3% b 23% c 8% d 220%22 a 40% b 36% c 104% d 430%23 a 0.13 b 0.08 c 0.068 d 0.075%
25 a 9 b 72 c 6 d $23.10e 21 kg f 0.75 m (or 75 cm)
26 a 6.6 min b $11.50
Chapter 11Start up
1 a 4 b 4 c 5 d 6e 10 f 7 g 6 h 14i 18 j 9 k 8 l 14
2 a 2 o’clockb 4:45 or ‘quarter to five’c 7:30 or ‘half past seven’d 1:50 or ‘ten minutes to two’e 12:35 or ‘twenty-five minutes to one’f 9:25 or ‘twenty-five minutes past nine’
3 a 4:15am b 1:20pm c 8:17pm4 a 1600 h b 0100 h c 0330 h
d 0515 h e 1838 h f 1230 hg 0846 h h 2130 h i 2217 h
5 a 6:00pm b 4:00am c 10:00pmd 5:30am e 1:30pm f 7:15pmg 7:30pm h 8:05pm i 9:45pmj 6:30am k 10:15am l 11:40am
6 a BC means Before Christ, AD means Anno Domini (literally meaning ‘in the year of the Lord’, means after Christ)
b 100 years c 12 months
24 Fraction Decimal Percentage
0.6 60%
0.8 80%
0.82 82%
14---
12---
215------ 5
14------ 1
21------ 3
4--- 1
2---
14--- 3
8--- 3
4--- 4
5---
16--- 1
2---
3235------ 1
2---
35---
45---
4150------
d 24 hours e 60 minutesf 365 days g 28, 29, 30 or 31 daysh 52 weeksi Each leap year has an extra day in February
to account for the four days.
7 a 1952, 1956, 1960, 1964, 1968, 1972, 1976, 1980
b 88 a 500 b 26 000 c 180
d 7 e 35 000 f 240g 0.601 h 0.0405 i 13 710
Exercise 11-011 a flour b fruit c rice
d salt e water f biscuitsg medicine h soft-drink i sugarj bricks k books l detergent
(Other answers possible.)2 a cm3 b cm3 c m3
d m3 e mm3 f m3
(Other answers possible.)3 a 3000 mm3 b 5 000 000 cm3
c 2600 mm3 d 4 cm3 e 7 200 000 cm3 f 66 cm3 g 1 000 000 000 mm3 h 0.0023 m3 i 126 m3 j 3.45 cm3 k 25 000 000 000 mm3 l 0.000 078 m3 m 0.063 m3 n 0.0014 cm3
4 Teacher to check. 5 D6 a E b G c F d C
e A f B g D
Exercise 11-021 a 225 cm3 b 1071 cm3
c 576 cm3 d 2295 cm3 e 27 cm3 f 39.6 m3 g 40 500 cm3 h 144.72 m3
2 Length Breadth Height Volume
a 50 cm 50 cm 50 cm 125 000 cm3
b 5 cm 10 cm 18 cm 900 cm3
c 4 m 2.5 m 1.4 m 14 m3
d 24 mm 16 mm 11 mm 4224 mm3
e 20 cm 10 cm 10 cm 2000 cm3
f 5 mm 2 mm 10 mm 100 mm3
g 6 m 1.5 m 3 m 27 m3
h 22 cm 8 cm 5 cm 880 cm3
i 70 mm 10 mm 100 mm 70 000 mm3
j 1.8 m 0.5 m 10 m 9 m3
14---
14---
17 NCM7 2ed SB ANS.fm Page 542 Friday, June 6, 2008 11:19 PM
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345678901234567845678901234567890123456789012
2345678901230128901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
543ANSWERS
3 a 62 cm3 b 126 mm3 c 498 m3 d 6400 cm3 e 23 552 m3 f 23 500 cm3 g 28 700 mm3
4 a 200 cm3 b 5625 mm3 or 5.625 cm3
c 5000 cm3 or 0.005 m3
d 3 m3 e 0.6 m3
Exercise 11-031 a 1 L, 600 mL, 300 mL
b 375 mL, 750 mL, 1250 mL, 2 Lc 375 mL d 250 mLe 50 L, 30 L f 2 000 000 Lg 9000 L h 250 mL
2 a mL b kL c L d mL e L(Other answers possible.)
3 a 7 L b 2000 mL c 3500 mLd 10 L e 2.5 L f 1500 mLg 4 L h 8500 mL i 6200 mLj 1.75 L k 5000 L l 9 kLm 25 000 000 L n 0.52 Lo 0.0023 L p 0.000 006 kL
4 A5 a D b G c J d H e I
f A g F h E i C j B6 87 a 54 L b 278 10 days9 a 0.2 mL b 12 mL
c 2160 mL or 2.16 Ld 17 280 mL or 17.28 L
10 6 h
11 a 2700 cm3 b 2700 mL 12 a 48 m3 b 48 kL = 48 000 L13 a 72 000 cm3 b 72 L
Exercise 11-041 a gram b tonne c kilogram
d tonne e kilogram2 Teacher to check.3 a 3 kg b 2000 kg c 4000 g
d 9 t e 7500 kg f 10 gg 1500 g h 3.8 t i 3000 mg
4 C5 a � b � c = d =
e = f � g � h � 6 a H b E c I d J e D
f A g B h C i F j G7 Teacher to check.
14---
Mental skills 112 a 8:45am b 1:20pm c 5:50pm
d 12:17am e 9:05pm f 6:32pmg 11:15am h 2:38am i 2:40pmj 3:20am k 4:55pm l 11:31pmm 1:08am n 10:18am o 8:00pmp 6:43am
4 a 1835 hours b 0805 hoursc 1145 hours d 2320 hourse 0221 hours f 1230 hoursg 1548 hours h 1911 hoursi 0908 hours j 2150 hoursk 0042 hours l 0739 hoursm 0159 hours n 2218 hourso 1046 hours p 1723 hours
Exercise 11-051 b 200 years
c
2 a 1 unit = 20 yearsb A 1851, B 1982, C 1956, D 1901, E 1813,
F 1974, G 1788, H 19323 a Teacher to check. b 1 unit = 4 years
c Sir Ninian Stephen or William Hayden (7 years)
d Viscount Dunrossil4 Teacher to check. 5 Teacher to check.6 Teacher to check.
Exercise 11-061 a seconds b hours
c minutes or secondsd days or months e hoursf minutes g days or weeks
2 a 4 hours b 12 hours c 6 hoursd 8 hours e 3 hours f 3 hours
3 a 18 minutes b 9 minutesc 4 minutes d 4 hours 20 minutese 12 minutes f 1 hour 29 minutes
4 a 360 minutes b 900 secondsc 63 days d 130 weekse 72 hours f 730 daysg 336 hours h 255 minutesi 204 hours j 630 secondsk 720 years l 42 days
5 a 8 minutes b 10 weeksc 4 days d 3 hours 20 minutese 9 years f 9 minutes 20 secondsg 2 days h 18 weeks
3000 BC 2000 BC 1000 BC AD 1000
753 BC AD 1
1600 BC
AD 17923111 BC
AD 622544 BC
12---
17 NCM7 2ed SB ANS.fm Page 543 Friday, June 6, 2008 11:19 PM
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8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
544 NEW CENTURY MATHS 7
i 5 minutes 30 secondsj 12 fortnights k 2 hours 15 minutesl 4 (or 4.7) centuriesm 6 hours 45 minutes n 2 hours 47 minutes
6 a 3600 seconds b 86 400 secondsc 31 536 000 seconds
7 Yes
Exercise 11-071 a 8:00pm b 7:00pm c 7:43pm
d 1:17pm e 2:08am f 1:32pmg 2:14am h 4:15pm i 6:17amj 3:25pm
3 A4 a 1 h 5 min b 1 h 50 min
c 5 h 44 min d 3 h 53 mine 5 h 45 min f 11 h 38 ming 2 h 25 min h 43 mini 1 h 47 min j 4 h 8 mink 7 h 39 min l 13 h 25 min
5 a 6 h 47 min b 11 h 52 minc 12 h 30 min d 8 h 9 mine 12 h 29 min f 12 h 7 min
6 a 3 h 29 min b 7 h 31 minc 6 h 9 min d 1 h 45 mine 4 h 51 min f 1 h 43 min
Exercise 11-081 a ahead b ahead c behind
d ahead e ahead f behindg ahead h ahead i aheadj ahead k behind l behind
2 a 10:00pm b 8:00pm c 7:00amd 8:00pm e 4:00am f 2:00amg 3:00pm h 1:00pm
3 a 2 hours b 2 hours c 20 hoursd 7 hours e 15 hours f 0 hoursg 3 hours h 13 hours i 7 hoursj 9 hours
4 a 4:00am b noonc 11:00pm night before d noone 8:00pm night beforef 6:00pm night beforeg 7:00am h 5:00am
2 Place Time
1st Joe 12:43pm
2nd Anna 1:14pm
3rd Ken 1:19pm
4th Pathena 1:21pm
5th Mike 1:31pm
6th Gail 2:02pm
710------
5 2:30pm 6 9:00am 7 B8 You gain or lose a day. The line is drawn this
way to keep a whole country on one side of the line and, therefore, on the same day.
Exercise 11-091 a ahead b ahead c same
d behind e ahead f behindg ahead h same i ahead
2 a h b 2 h c h
d h e 2 h f 0 h
3 a 11:00pm b 10:30pm c 9:00pmd 10:30pm e 11:00pm f 11:00pm
4 a 12:00 midnight b 12:00 midnightc 10:00pm d 11:30pme 12:00 midnight f 12:00 midnight
5 a 4pm b 3pm6 d 3:30pm
Exercise 11-101 a 1 hour 25 minutes b 20 minutes
c TH038 d TH1142 a 7 hours b 6 h 30 min
c 4 h 11 mind Liverpool to Sydney 1 hour, Sydney to
Liverpool 1 h 15 min. More traffic on the road as school finishes around 3:30pm.
3 a 7:27am b 27 min c 46 mind Teacher to check.
e am
GOULBURN 11.12
MARULAN
TALLONG Bookings
WINGELLO essential
PENROSE
BUNDANOON 11.47
EXETER
MOSS VALE 12.00
BURRADOO
BOWRAL 12.06
MITTAGONG 12.11
YERRINBOOL
BARGO
TAHMOOR
PICTON
C’TOWN 1.07
S’FIELD 1.37
CENTRAL 1.49
12--- 1
2---
12---
17 NCM7 2ed SB ANS.fm Page 544 Friday, June 6, 2008 11:19 PM
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3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
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78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
545ANSWERS
4 a 5 buses; Bus 1 can do the 10:00am and 12:00noon trips.
b At Zoo at 12:45pm, first bus after 11:42am at station is 12:00noon.
c Teacher to check.
Power plus1 3150 mL or 3.15 L2 8 cm3 a 45 m2 b 13.5 m3 c $10.804 54.16 ≈ 54 drops5 a 500 b 12.5 tonnes6 a 3072 cm3 b 20 000 cm3 7 6 cm8 2:00pm9 Lose a day
10 1 m3 = 1 000 000 cm3 = 1 000 000 mL = 1000 L = 1 kL
Chapter 11 revision1 a 20 000 mm3 b 500 000 cm3
c 7.5 cm3 d 0.23 m3
2 84 cm3 3 a 80 m3 b 320 cm3
c 672 mm3 d 360 m3 e 3000 cm3 f 870 m3
4 2 × 1015 = 2 000 000 000 000 000 L5 a 2 L b 3000 L
c 7000 mL d 3.3 kLe 1.75 L f 2500 mL
6 B 7 216 t8 a 5 kg b 2000 mg
c 1500 kg d 6.5 te 4 g f 1500 g
d Depart
Explorer depot 11:30 1:30 2:30
City cathedral 11:38 1:38 2:38
Railway station 11:45 1:45 2:45
Parliament 11:54 1:54 2:54
Museum 12:05 2:05 3:05
City square 12:15 2:15 3:15
Zoo 12:30 2:30 3:30
Dockland shops 12:42 2:42 3:42
Arts centre 12:49 2:49 3:49
Water gardens 1:00 3:00 4:00
Hall of fame 1:08 3:08 4:08
Arrive
Explorer depot 1:20 3:20 4:20
9 Teacher to check10 a 10 h b 3 h c 4 h11 a 3 min b 11 min c 3 h 24 min12 a 8 weeks b 240 min c 16 min
d 260 weeks e 168 h f 12 h13 a 3:42am b 7:51am
c 6:20pm d 5:43pme 10:34pm f 6:55pm
14 a 4 h 19 min b 7 h 34 minc 6 h 47 min d 6 h 35 mine 19 min f 23 h 59 min
15 a 10 h 5 min b 1 h 50 minc 6 h 57 min d 1 h 29 min
16 a 8:00am b 9:00pm day beforec 9:30am d 3:00ame 8:00am f 4:00pm day before
17 a 2am b 12 midnightc 1:30am d 2am
18 a 3 h 19 min b 9:05
Chapter 12
Start up1 a 11 b 12 c 2 d 16
e 24 f 56 g 4 h 4i 5 j 21 k 4 l −2
2 a 15 b 60 c 5 d 29e 400 f 40 g 40 h 11i 22 j 46 k 0 l 0
3 a −12 b −10 c −16d −2 e −14 f 12g 20 h 6 i −1
4 a 0 b −3 c −2d 1 e 7 f 0g −5 h 4 i −5
5 a 5 b 1 c −1d 6 e 1 or 1.5 f 7g 10 h 1 i 5
6 a x −1 0 1 2
y 1 2 3 4
b n −1 0 1 2
m −5 0 5 10
c c 1 2 3 4
d 2 5 8 11
d m 5 6 2 −1
l 25 36 4 1
12---
12---
17 NCM7 2ed SB ANS.fm Page 545 Friday, June 6, 2008 11:19 PM
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8901234 3456789012345634567890123456789012 7890129012345678901234567890123456
3456 1234567890123456789078901234567890123456789012342345678901234567890123456789
67890123456789012345678901234123456789012345 234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
78901234567890123456789012345234567890123456789012345678978901234567890123456789012342345678901234567890123456789678901234567890123456789012341234567890123456789012345678
5678901234567890123456789012301234567890123456789012345675678901234567890123456789012
90123456789012345678901234567456789012345678901234567890129012345678901234567890123456
3456789012345678901234567890189012345678901234567890123453456789012345678901234567890
012 3456789014567890123456789012
67890123 4567890123 8 0123456789
567890123 8901234789
0123456789
0123456789
1234
546 NEW CENTURY MATHS 7
Exercise 12-011 B
2 a b
c d
e f
g h
i
j
k
l
3 a k + 2 b 2k + 3c 2 + 2k d 3k + 4e k + 1 + k + 1 f 2 + k + 2 + 2kg 1 + k + 3 h 2k + 2 + 2k + 1i k + 3 + k j 5 + 4k
4 a y + 2 b 3y + 1c 1 + y + 1 d 4 + y + 2e y + 1 + y + 1 f 2y + 2 + y + 1g y + 2 + y h 4yi y + 4 j 2 + y + 1 + y + 2 + y
5 a m + p b 2p + 2m c m + p + m d p + m + p + m e 2m + p f 3m + 2pg p + m h m + p + m + p + m i 2p j 3m k p + 2m l m + 2p + 2m m 2m + 2p n p + m + p + 2m
6 f, h, l, n
Exercise 12-021 a 2 b 3 c 1 d 3
e 2 f 3 g 1 h 2i 3 j 3 k 4 l 2m 4 n 2 o 1 p 6
2 a 20 b 18 c 6a d 4e e 2w f 13m g 14h h 3m i 40k j 3w k 10p l −n m 3a + 2b n 6d o 0 p 9q
3 a 4w b 8ab c 3acd d 5abc e 6hw f 6fg g 6cmw h 8bhms i mw j 30dpqry k a2 l d3 m 4f 2 n 2g2 o 4h3 p 8l2 q 8m2 r 36r3 s c2e3 t 35j2k u y3z2 v 24n3p2
4 It could mean 53. 5 A × B
6 a A × B b 2 × m × n × s c 188 × A × B × C d 3 × m × n × a × b × c × d × e × f e 4 × m f 1 × m g x × x h q × q × qi 7 × d × d j 5 × s × s × s k x × x × y × y × y l 9 × m × m × m × n × n
7 D
Exercise 12-031 a 2N or 2 × N b N ÷ 2 or or N
c 3N or 3 × N d N ÷ 4 or or N
e N ÷ 10 or or N
f N + 1 g 5N or 5 × N h N + 21 i N − 10 j N + 2k N + 3 l N2 m
2 No, it makes no difference at all.3 a A + B b A + B + C
c B − C d AC e ABC f A ÷ B or
g (A + B) ÷ C or h C ÷ B or
4 a 3 + A b B − 3c C + 5 d D + 8 or 8 + De E − 3 f X − Fg A + B + W h m ÷ m or
i R2 j (A + B) ÷ 2 or
5 a B + G b 2 × N or 2N c T − X d 2N e M ÷ 3 or f A + 2B
6 A
Exercise 12-041 a and D, b and A, c and F, d and B, e and C,
f and E 2 a and D, b and F, c and A, d and B, e and C,
f and E 3 a 2p + m b m + p
c 2m + 3p d 3p + 5 e m + 2 f 2p + 2m + 1g m + 3 h 2p + m i 2p + 1 j 2m + 2p
4 a 5m b 5p c m d 2m + 5p e 4m + 6p f 3m + 4p g 4m + 4p h 2m + 7pi 9m + 4p
5 C
N2---- 1
2---
N4---- 1
4---
N10------ 1
10------
N
AB----
A B+C
-------------- CB----
mm----
A B+2
--------------
M3-----
17 NCM7 2ed SB ANS.fm Page 546 Friday, June 6, 2008 11:19 PM
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547ANSWERS
Mental skills 12A2 a 160 b 70 c 240 d 900
e 2600 f 900 g 2200 h 300i 180 j 400 k 1100 l 210m 700 n 1800 o 390 p 770
Exercise 12-051 a 3x and 16x b 2mw and 5mw
c 2w and 23w d 2p and 5p e 2k and 3k f 2ab and 3ba g 3x2 and x2 h 4mn, 2nm and mn i x2y and 4x2y j 7, 9 and 2k q2 and 2q2 l cd2 and 5cd2
2 C3 a 7m b 11k c 7ab d 7mn
e 2xy f 9abc g 9ab h 20mn i 14cde j 16mp k 6x2 l 5ef 2
4 a 2m b 5d c 5mk d 33abc e 32fg f 19mn g 18cd h 4xy i −4de j 3k2 k 3w2 l 2xy2
5 a 4m b 3a c 15x d 9f e 9s2 f 7mn g 2pq h 9abc i 0 j −3d2 k 0 l 16de
6 a 8x + 10 b 8m + 4c 7mn + 10f d 4k + 8e 40xy + 6ab f 15 − r g 11 − p or −p + 11 h −3k − 5i 12 − 4ab or −4ab + 12 j −2abk 8m − 3p l d − 5dem 5y2 + 7y n 3m2 + 5n2
o 11g2 − 5 p 5x2 − 10x 7 a 9m b 4k + 2 c 16mx
d 5d + 9 e 6f + 10g f 12y + 5x g 10p h 4 + 5q i 3abc j 15k + 22 k 9a + 9b l 13x2 m 5y + 6 n 5r + 2s o 2x + 6p 3a q 6m2 − 6 r 4pq s 11x + 3y2 t 8ab + 10cd
8 C
Exercise 12-061 a 6y b 56q c 12t
d 27k e 8d f 12abg 48cd h 54pq i 6m2
j 55k2 k 108f 2 l 72gh m 120mn n 84a2 o 84x2
p 30m2 2 a 72ab b 8mn c x2y2
d 42jk e 10r2s2t f 18abcd g 9p h 2m2n i h2j3k2 j 24p2q2 k 108x3y3 l 6m2n2
3 a −18x b −6k c −p d −4j e −6m f −12y g 4n h 5k i r j 56x k s2 l 3d2
4 B
Exercise 12-071 a 3a + 6 b 2h + 4 c 2m + 6
d 4x + 24 e 8m + 12 f 7a + 7b g 24p + 60 h 5a + 10 i 18x + 24j 24m + 12n k 40p + 20q l 6a + 12b
2 a 4x − 8 b 3m − 21 c 8k − 24d 5y − 25 e 2m − 2p f 21f − 14g g 12m − 20 h 15m − 15 i 18x − 24j 3 − 3k k 12 − 18p l 20 − 20m
3 a −3x − 6 b −7p − 7 c −2m + 6d −5k + 20 e −24 + 4y f −9a − 36g −k − 3 h −m + 2 i −6 + 2xj −12m − 15 k −15y + 30 l −4 + 7x
4 a mn + ms b xy − 2xc km + 12k d pq − 4p e 2xy − 3y f 4fk − 7f g 2ab − 6b h 2np + 7ni 6km + 2m j 15kx − 6k k 4m − 4m2 l x2y + 2xy m 35wx − 10mw n 10bc − 6ac o 18pq + 6pr p 20jk + 28jl
5 a x2 + 4x b 2a2 + 5ac −n2 − 2n d 2y2 − 8y e −2r2 + r f p2 + pq g −d2 − de h 8w − w2
i −3v2 − 21v j p2q + pq2
k −m + n l −3k2 + 3k m 2m2n + 3mn2 n −2k − 4j o a2b + ab2 + abc p 4m2 + 8mn + 12mp
6 A 7 D
Exercise 12-081 a 5p + 2q b 7a + 26 c 3k − 8
d 8 + 2n e 17k + 22 f 16v + 48g 8t − 32 h 3a − 2 i 4x − 6j 10x − 3 k 2x − 3 l −2
m 4 n x + 22 o 2 − 6x p 12 − 5x
2 D3 a 6x + 8 b 5r + 1 c m2 + 4m + 3
d 7q + 31 e 7d + e f 2x + 8 g 6 h 4x − 20 i 4y − 26j 12m − 6 k 2d − 2 l 34t + 23m 30m + 12 n 12p + 2q o 11m + 3n p 3k + 31
4 a wrong g wrong5x − 2 + 3x 2p − 3 − 3 + 4p = 8x − 2 = 6p − 6
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548 NEW CENTURY MATHS 7
h wrong9x − 1 + 3x − 5 = 12x − 6
Mental skills 12B2 a 18 b 34 c 46 d 66
e 26 f 16 g 8 h 44i 12 j 40 k 28 l 40
m 18 n 8 o 36 p 140
Exercise 12-091 a 5 b 21 c 122 d −182 a 40 b 58 c 17 d 03 a 8 b 44 c −16 d 324 a −14 b 51 c 106 d 1915 a 20 b −78 c 160 d 1746 a 5 b 13 c −3 d 197 a 8 b 41 c 68 d 54
e 55 f −76 g 1.25 h 19i −2 j 3 k 10 l 65m 9 n 42
8 D9 a 2 b 35 c 24 d 31
e 3 f 28 g 18 h 29i 58 j 80 k 100 l 170
10 Values 2x + y xy 8x 3x − 2y 37 − 4y
a x = 3 and y = 4 10 12 24 1 21
b x = 4 and y = 0 8 0 32 12 37
c x = −2 and y = −1 −5 2 −16 −4 41
d x = 5 and y = 6 16 30 40 3 13
ex =
and y = 1 4 35
f x = 8 and y = 9 25 72 64 6 1
g x = 21and y = 5 47 105 168 53 17
h x = 0 and y = 8 8 0 0 −16 5
i x = 2.5 and y = 1.5 6.5 3.75 20 4.5 31
jx =
and y = 1 6 1 35
k x = 3 andy = −4 2 −12 24 17 53
l x = 0.7 and y = 0.2 1.6 0.14 5.6 1.7 36.2
12---
12---
12--- 1
4--- 1
2---
34---
25---
910------ 3
10------ 9
20------ 2
5---
11 a 7 b 104 c 26 d 65e −20 f 12 g 25 h 0i 1 j 0 k −260 l 24
m 2107 n 0 o 400 p 45
Power plus1 a 5a − 3b b −4m − 10n
c −k + 4j + 4 d 5b2 e 3x2 − 6x f 5xy + 2yz + 4xz g 2a + 4b + 6c h −4p − 9q i −4d2 + 4e2 + 16 j 13f 2 + 6f + 1
2 a x − 7 b m + 12c x2 + 2x − 15 d 2am − 3m e 4y − 9 f 6a − 2b + 14c g −5p2 − 7pq + 10pr h 4k2 − 5k − 5i 27 − 20f + 30g j −2x2 + 7x + 115k x2 + 8x + 15 l p2 + 9p − 10
3 Teacher to check.4 a −2 b −24 c 10 d 9
e 8 f 16 g 7 h 4i −1 j 3 k 1 l 0
5 a P = 2l + 2b or 2(l + b)A = lb
b P = 2 + y + x + y + 2 + x or 2(x + 2 + y)= 4 + 2x + 2y
A = x(2 + y)c P = p + q + r
A =
d P = m + 5 + m + 3 + n = 8 + 2m + n
A = mn + × 3 × n = mn + e P = x + y + y + x + x
= 3x + 2y A = x2 + × x × 2
= x2 + x f P = a + b + c + (b − d) + (a − c) + d
= 2a + 2b A = ad + c(b − d)or bc + d(a − c)or ab − [(a − c) × (b − d)]
6 a x b x c 0 d 1 e 0f 2x g 0 h x i x2
Chapter 12 revision1 a 2m + 2 b m + 1 + m + 2
c 3m + 42 a 10a b 24abc c 80mw2 3 a 5 × m b 4 × m × n × k
c 6 × a × b d a × b × c 4 a 3N b N − 5
c N + 1 d N or
15---
pq2-----
12---
3n2
------
12---
13---
N3----
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549ANSWERS
5 a A + C b ABC c C − B
6 a M + 3 b B + 5c 2H − k
7 a 8p b 4y c 3d d −5x − 4y
8 a 2a and 3a b 3mn and 8nm c 2xy, yx and 4yx d 3a2b, 4a2b and ba2
9 a 10a b 6mn c 2abc d 20w + 8e 11a − 11b f −2a − 2b g −5x + 2y h 4a2 + 3ai 2xy
10 a 15bd b −12hn c −10a2b
11 a 7e + 28 b 5k − 40c 2y − y2 d m2 + 2m e −3j − 6 f −2t + 8g 9a2 − 18a h 10k − 2k2
12 a 7w + 6 b 6h + 6c 10x + 17 d 11 − a e y + 2 f 5d + 25g 2m + 9 h 20c + 8i 21p + 5
13 a −7 b 26 c 11 d 15
Chapter 13
Start up1 x = 60
2 a i ii 120° b i ii 90°
c i ii 72° d i ii 60°
e i ii 135° f i ii 180°
3 a one interval = 5 b one interval = 1.5c one interval = 2 d one interval = 1e one interval = 3
(Teacher to check scale diagrams.)4 a G b F c I d H e D
f E g A h B i C j J5 a 10 cars
b 5 cars. It is difficult to represent the whole range of values accurately.
c 8:00–10:00am d 6:00–8:00am
14 Values 2a + 3b 3a 4b 2ab 5a − 2b
a a = 3 andb = 4
18 9 16 24 7
b a = 5 andb = −1
7 15 −4 −10 27
13--- 1
4---
15--- 1
6---
38--- 1
2---
e 6:00–8:00am, 5; 8:00–10:00am, 40; 10:00am–12:00noon, 10; 12:00noon–2:00pm, 20; 2:00–4:00pm, 35; 4:00–6:00pm, 15
f i 8:00–10:00am dropping children at school, going to work
ii 6:00–8:00am not many people around yet, a few going to work
iii 2:00–4:00pm parents picking up children.
6 a Sydney b Darwinc 0.2 million people or 200 000 peopled 1.8 million e Adelaidef About 18 times
7 a 12:50pm b Hurstvillec 24 min d 4:12pme The train doesn’t stop at that station.f 1 h 37 min
Exercise 13-011 a $2 billion b Financial years
c 2006–07 d About $11 billione 2001–02f i 2001–02 ii Teacher to check
iii 2001–02 iv About $1 billion.2, 3 and 4 Teacher to check.
Exercise 13-021 a i $10 ii $35
b i 2002 ii 2006c 2002 and 2003 d $30 000e About $80–$85
2 a 1 Julyb Garbage 55 000 t Recycling 9000 t
Garden waste 5000 tc 5000 td Garden waste was not collected.e 2006–2007f Put into other categories.
3 a i 99% ii 88% iii 88%b Dishwasher c Mobile phonesd About 15% e Teacher to check.
4 a 6:00–7:00pm, 46 b 14c 8:00–9:00pm d 98e 4:00–5:00pm, people were still at work
5 a 1 unit = 10% b 45% c 2006d i 3 and 4 ii 5 and overe 3 and 4 f True
6 a About 25 100 b Western Australiac A decrease in populationd NSWe About 3000f About 2500
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550 NEW CENTURY MATHS 7
g Queensland, people retiring to better climate and more affordable housing
h Tasmania, smallest state, isolated from mainland
7 Teacher to check.8 a Within 5 km of home
b = c =
d Fewer accidents occur. Most travelling is done close to home.
e = f True
9 a 100 mmb Meet community needs, =
c
d Meet community needs, decrease cost, save natural resources, reduce pollution, and others.
e Teacher to check.10 a O + b AB − c 7%
d 1 mm = 1% e False
11 a Australian football = × 12 = 4 cm
Horse racing = × 12 = 2.8 cm = 28 mm
Rugby League = × 12 = 2.4 cm = 24 mm
Soccer = × 12 = 1.6 cm = 16 mm
Cricket = × 12 = 1 cm = 10 mm
Other = × 12 = 0.2 cm = 2 mm
b Teacher to check.12 Teacher to check.
Exercise 13-031 a Capricciosa
b Mexicana, Marinarac Capricciosa 180°; Hawaiian 90°;
Marinara 45°; Mexicana 45° d 72
3 a The number of people hurt in accidents in different jobs.
b Farmhands and assistantsc Truck drivers or some group in ‘other’d 76.4% e True
4 a dog b goldfish
c i = ii = d Noe Dog 27 Bird 12
Cat 24 Guinea pig 18Goldfish 9
5 Teacher to check.
44100--------- 11
25------ 75
100--------- 3
4---
6100--------- 3
50------
28100--------- 7
25------
21100---------
2060------
1460------
1260------
860------
560------
160------
330------ 1
10------ 4
30------ 2
15------
6 a Mortgageeb Private Australian investor; just under c Private Australian investord 6 ef Mortgagee, Foreign
Exercise 13-041 a i 70 cm ii 120 cm
b i 4 ii 11c 0 and 1, babies grow quicklyd 6 and 7, children’s growth slows downe 3 yearsf 10 years, growth slows downg i fairly flat ii possibly horizontalh Teacher to check.
2 a 8% b 40 to 50 years of agec 7%d More likely to die from cancer and heart
disease.e True f Between 25 and 60g Between 18 and 42
3 a A Melbourne, B Sydney, C Brisbane, D Adelaide, E Perth, F Darwin, G Canberra, H Hobart
b Jan 28°, Feb 27°, March 24.5°, April 19.5°, May 15°, June 12°, July 11°, Aug 13°, Sept 16°, Oct 19°, Nov 23°, Dec 26°
c March and Decemberd B June C July
D May E June, Septembere F f G, 15° in Decemberg 33°, F, November h 0°, G, July
4 Teacher to check.5 Teacher to check.6 a April 22, 24°C b 15°C
c 9°C d 1 unit = 1°Ce 16°C f April 20, April 21g 16th h 5
7 Teacher to check. 8 Teacher to check.
Exercise 13-051 a 1 unit = 1 km b 1 unit = 20 minutes
c 15 km d 10:30ame 1 hour f 1:20pmg 2 h 40 minh They stopped for 20 minutesi 30 km
2 a 11:00am b 40 kmc at noon and 1:30pm d 45 mine after 1:45pm, graph is steepest
3 a 1 unit = 0.4 acres b 4.9 hectares
12---
18---
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551ANSWERS
c 2 hectares d 10.8 acrese 12.4 acresf i 32 000 m2 ii 3.2 ha iii 8 acres
4 a € 9 b €30 c €60 d Truee $84 f $34 g €72
5 Teacher to check.
Exercise 13-061 a i $12 ii $16 iii $16
b Teacher to check.c A shaded circle means include that value.
A clear circle means do not include that value.
d You wouldn’t know which value was correct.
e More than 3 hours up to 4 hours.f You are charged $20 for all times over 4
hours.2 a i $10 ii $14 iii $19
iv $22 v $16 vi $14b More than 4 hours, up to 5 hours.
3 a 1 unit = 250 gb i $6.75 ii $6.10 iii $5.20c i $2.75 ii $3.75 iii $5.20d $6.40e i $15.75
ii Cost together $6.75, save $9.f More than 250 g and up to 500 g.
4 a $6b i $5 ii $4 iii $3.50c Decreases, bulk discountsd $3.50 e 50f More than 5 boxes and up to 10 boxes,
i.e. 6, 7, 8, 9 or 10 boxes
Mental skills 132 a
b
c
d
e
f
36 56 °C40 44 48 52 60 64
200 mL240 280 320 360
500 g520 540 560 580
30 L45 75 90 10560
160 280200 240 min
200 kg300 400 500 600 700
38 42 46 50 54 58 62
210 220 230 250 260 270 290 300 310 330 340 350 370
504 508 512 516 524 528 532 536 544 548 552 556 564 568 572 576 584 588 592
35 40 50 55 65 70 80 85 95 100 110 115
170 180 190 210 220 230 250 260 270 290 300 310
220240260280 320340360380 420440460480 520540560580 620640660680
g
h
120 seconds180 240 300 360 420
100 mL300 400 500 600 700200
135 150 165 195 210 225 255 270 285 315 330 345 375 390 405
125150175 225250275 325350375 425450475 525550575 625650675 725
Exercise 13-071 a i $8.20 ii $9.50
iii $10.80 iv $19b 1 adult and 3 childrenc i $16.40 ii $21.60
iii $25.80 iv $48.902 a i 745 km ii 304 km
iii 1736 km iv 4342 kmb Brisbane, Perthc Brisbane and Perthd Canberra and Sydneye Teacher to check.f i 655 km ii 238 km
iii 489 km iv 1202 kmg Air distance is less than road distance
because it is a more direct (straight-line) route than a road could be.
h Adelaide and Sydney3 a 8 b AB+, B+
c O−, O+, B−, B+ d O−e AB+ f O−
4 a TH414b 1700 hc Saturday, Sunday
d1 h 25 mine TH418f Saturdayg Monday, Wednesday, Saturdayh Monday, Wednesday, Fridayi TH415j The airports are in different time zones.
5 a i $14.90 ii $9.50b Supreme, Marinarac $2.50 d $23.50 e 14
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552 NEW CENTURY MATHS 7
Power plus1 a Spain b About $700 million
c 2003–04 d About $650 millione 2002–03 f 2002–03g increased by a lot h Spain
2 a residentialb i $34 billion ii $44 billion
iii $73 billionc $97 billion d increased
3 a 39 km b 543 km c 279 km
Chapter 13 revision1 a 0–4 years b 13.5%
c It covers more years than each of the other groups.
2 a 26%b Anglican, Other Christianc There would have been almost no
Buddhist, Muslim or Other.3 a United Kingdom b
c 1667 people4 a Broadband b
c 768 0005 a January and February
b January and Februaryc Octoberd June and July
6 a 80 km b 1 unit = 5 kmc 11am d 5 hourse 45 km
7 a 1 unit = $60b i $120 ii $240 iii $210c $40 per hourd More than 2 and up to 3 hours
8 a $47 b $564 c $39d $1170 e $60
d Sydney
Liverpool 39
Goulburn 150 189
Yass 83 233 272
Gundagai 100 175 325 364
Holbrook 114 214 289 439 478
Albury 65 179 279 354 504 543
Wangaratta 72 137 251 351 426 576 615
Benalla 41 113 178 292 392 467 617 656
Euroa 48 89 161 226 340 440 515 665 704
Seymour 53 101 142 214 279 393 493 568 718 757
Melbourne 100 153 201 242 314 379 493 593 668 818 857
710------
37100---------
Mixed revision 41 a b c d
2 a 2 b 3 c 1 d 1
3 a 6 b 204 Teacher to check.5 a b c d
6 a � b � c �
7 a b c d 3
e 2 f 1 g h 1
8 a $12 b 0.5 m or 50 cm c 4
9 a b c 8 d 1
10 a 1 b c 4 d 3
11 a 25% b 60% c 11 % or 11.1%d 216 % or 216. %
12 a 40% b 5% c 120% d 203%13 a i $10 ii 720 iii 0.1 h or 6 min
iv 0.08 tonnes or 80 kgb 1 pair
14 a 2 g b 2000 kg c 8 weeksd 6500 mL e 72 hours f 4000 gg 1.5 kg h 3 L i 8 minj 2.5 t k 9500 mg l 12 kg
15 a 45 m3 b 330 cm3 c 11 880 mm3 16 4 hours 17 7 h 25 min18 a 5 h 25 min b 1 h 10 min
c 11 h 41 min d 7 h 5 min19 a midnight b 5:00pm c 6:00am
21 a w + 8 b k − 9c 5g d m or e p − 7 f t + 1
22 2a, a, 10a 23 a 10p b 5q c 6a + 10b
d 10x + 3y e 12k + 19 f 63ac g 9p2 h 36m i 27a2 j 80m
24 a 2x + 8 b 7k − 14 c m2 + 4m25 a 4g + 4 b 9y + 18 c p + 2126 a 14 b 12 c 15 d 1627 a −1 b −12 c 6 d 16
20 a x −1 0 1 5
y −3 −2 −1 3
b y 0 2 4 6
p 1 5 9 13
32--- 15
4------ 17
8------ 73
10------
25--- 1
2--- 2
3--- 5
6---
45--- 2
3--- 5
8--- 7
10------
13--- 1
4--- 2
5--- 5
10------ 5
7--- 3
5---
56--- 11
15------ 1
8--- 1
10------
215------ 1
10------ 59
84------ 1
4---
45---
310------ 7
8--- 1
3---
12--- 1
25------ 1
6--- 3
4---
19---
23--- 6
.
12---
m2----
17 NCM7 2ed SB ANS.fm Page 552 Friday, June 6, 2008 11:19 PM
Page 56
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553ANSWERS
29 Teacher to check.30 Teacher to check graph.
a 30 USD b 11 AUD
General revision1 a 3 × 7 = 21 b 7 + 3 = 10
c 12 ÷ 4 = 3 d 2 × 4 + 3 = 112 9100 3 69234 a 2 b 19 c 155 4 + 7 × 2 = 186 a 70° b 150° c 25°
7 a i ∠ACB and ∠CFG, ∠BCF and ∠GFH, ∠ACD and ∠CFE, ∠DCF and ∠EFH ii AH
b i 105° ii 75° iii 75° 8 a 1, 4, 9, 16, 25 b 1, 1, 2, 3, 5
c 2, 3, 5, 7, 119 85
10 a 72 b 7 c 5 d 100011 3, 1112 a 1, 2, 3, 6, 9, 18 b 913
14 a rectangular prismb triangular pyramid c cylinderd triangular prism e square pyramid
15 Teacher to check.16
28 y y + 4 3y 8 − y
0 4 0 8
1 5 3 7
3 7 9 5
7 11 21 1
240
2410
5 6
×
×
2 2× 3×5 ×
4×
× 2
× 2
2 ×
240 = 24 × 3 × 5
a i ii
iii
17 a b c
18
19 −4, −7, −1020 a −2 b −12 c 13 d −56
e 120 f 100 g −9 h −221 a M(2, 1) b N(−1, 0) c P(−2, 3)22
24 a 70 b c d 7000
25 a 2.6 b 3.07 c 5.31426 a 4.3 b 1.07 c 2.09
27 a b c
28 a 1.7 b 0.7 c 1.029 a False b True c True30 61 shirts31 a 7200 mm b 4.25 m c 84 000 cm2
32 a 1 cm b ± cm33 a 42 mm b 40 cm c 16 cm34 a 30 cm2 b 95 cm2 35 112 cm2 36 a quadrilateral
b ∠A = 56°, ∠B = 70°, ∠C = 134°, ∠D = 100° 37 Teacher to check.38 trapezium
23 a m 5 0 −2 10 12 −3
y 15 0 −6 30 36 −9
b j 20 12 4 7 1 −2 −4
k 16 8 0 3 −3 −6 −8
b i ii
41−2 −1 2 3 50
y5
4
3
2
1
4
321−2 −1 −1
T
S
R
x
71000------------ 7
10------
720------ 1
10------ 3
250---------
12---
17 NCM7 2ed SB ANS.fm Page 553 Friday, June 6, 2008 11:19 PM
Page 57
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554 NEW CENTURY MATHS 7
39
Equal diagonals bisect each other at right angles.
40 Teacher to check.41 • Opposite sides equal and parallel
• Four right angles• Diagonals are equal and bisect each other• Two axes of symmetry• Order of rotational symmetry 2
42 a = b =
c = d =
43 a b c 1 d 5
44 a $9 b 16 m c 200 mL45 a 73% b 75% c 60% d 47% 46 a $20 b 4 kg47 168 m3 48 a 0.24 t b 6 700 000 cm3 c 6700 L49 2000 packets
50 40 minutes or 2430 seconds
51 9:19am 52 25 cups53 a 5x b 9m c 10k
d 12p e 9a + 9b f 27x + 6y 54 a 6 m b k2 c 6p2 55 a 4m + 8 b 9y − 18 c 3d2 + 12d
Appendix 1
Exercise A-011 a 5068 b 14.5 c 45 d 5.724
e 3.5 f 26.9 g 23 h 1.68i 160 j 29.48 k -8.084 l 12.42
2 a $19.15 b 85 cents3 $1875.50 4 7542 kg5 2.4 m 6 $11.25
812------ 2
3--- 4
25------ 16
100---------
1520------ 3
4--- 2
5--- 20
50------
910------ 5
12------ 1
8--- 1
2---
12---
7 23 trees 8 75.2 km9 $85.74 10 13 buses
11 a $41.20 b $1318.4012 53.4
Exercise A-021 a 7 b −9 c −12 d −8 e 15
f −15 g 75 h 5 i −5 j 7k −96 l 45 m −25 n 24 o 96p 14 q −16 r 15 s −36 t 10
Exercise A-031 a 196 b 529 c 216
d 1.728 e 26.3169 f 10201g 4.1616 h 6859
2 a 26 b 5 c 9 d 1.5e 9.3 f 14 g 2.1 h 148
3 a 4.9 b 10.0 c 2.2 d 6.44 a 16 b 156 c 56 d 1206
e 6 f 2 g 105 a 11.49 b 1.4 c 42
Exercise A-041 a b c d e f
2 a b c d e f
3 a b c
d e f
4 a 0.5 b 0.8 c 0.875d 0.36 e 0.17 f
5 a b c
d e f
6 a b = c =
d e f
g h i
j 6 k l
m n o
7 hours 8 hours 9 40
10 a hours b $159.38
11 208 songs 12 hours
23--- 1
2--- 1
3--- 4
5--- 6
7--- 4
5---
114
------ 163
------ 307
------ 335
------ 313
------ 536
------
335--- 32
7--- 55
8---
7 211------ 12 3
10------ 19 1
12------
0.5̇7
20------ 2 1
25------ 1
1000------------
73200--------- 1 3
50------ 13
40------
110------ 15
14------ 1 1
14------ 19
15------ 1 4
15------
114------ 11
2--- 111
24------
415------ 21
32------ 11
6---
356--- 25
8---
418--- 151
9--- 1
10------
1712--- 63
4---
1234---
4258---
17 NCM7 2ed SB ANS.fm Page 554 Friday, June 6, 2008 11:19 PM