FRACTIONS, DECIMALS & PERCENTS OH MY!

FRACTIONS, DECIMALS &

PERCENTSOH MY!

The table shows the heights of the ten tallest buildings in Dallas.

Dallas’ Tallest Buildings

Building Height (ft)

Bank of America Plaza 921

Renaissance Tower 886

Bank One Center 787

JP Morgan Chase Tower 738

Fountain Place 721

Trammell Crow Center 686

1700 Pacific Avenue 655

Thanksgiving Tower 645

Energy Plaza 629

Elm Place 625

1. What fraction of the buildings are between 600 and 900 feet tall?

2. Write this fraction using words.

3. Write this fraction as a decimal.

1. 9 out of 10, which is 9/10

2. Nine-tenths

3. 0.9

To change a fraction into a decimal, you divide the NUMERATOR by the DENOMINATOR.

For example, to change into a decimal, you would

divide the 3 by the 4.4

3

344

3 0.34

0.7

-2 8 20

5

-2 0 0

75.04

3

This is called a TERMINATING DECIMAL. (it comes to an end, as in terminate a game!)

To change a fraction into a decimal, you divide the NUMERATOR by the DENOMINATOR.

Write each fraction or mixed number as a decimal.

20

70.720

0.3

-6 01 00

5

-1 0 0 0

35.020

7

This is called a TERMINATING DECIMAL. (it comes to an end, as in terminate a game!)

Example 1:

To change a fraction into a decimal, you divide the NUMERATOR by the DENOMINATOR.

Write each fraction or mixed number as a decimal.

4

35 75.5

4

35

Memorizing some conversions like these will make things a lot EASIER!

Example 2: We already know that ¾ =

0.75

¼ = 0.25 ½ = 0.50 ¾ = 0.75 (one quarter) (half of a dollar) (three quarters)

To change a fraction into a decimal, you divide the NUMERATOR by the DENOMINATOR.

Write each fraction or mixed number as a decimal.

8

32 375.2

8

32 Example 3:

0.38 0.3

-2 4 6 0

7

- 5 6 4 0

5

- 4 0 0

To change a fraction into a decimal, you divide the NUMERATOR by the DENOMINATOR.

Write each fraction or mixed number as a decimal.

3

13.0...333.0

Example 4:0.13

0.3

- 9 1 0

3

- 9 1 0

3……..

- 9 1

This is called a REPEATING DECIMAL. (a pattern in the digits repeats forever!)

You can use BAR NOTATION to indicate that a number repeats forever. A bar is written over the digit(s) that repeat.

Example 5: Write 7/9 as a decimal.

0.79 0.7

-6 3 7 0

7

- 6 3 7 0

- 6 3

7

7…7.0...777.0

9

7

To change a decimal into a fraction, you place the decimal number over the correct pace value position as a fraction ( #/10 #/100 #/1000)

For example, to change 0.25 into a fraction, you would place 25 over a denominator of 100 since it is read “twenty-five hundredths”.

25/100 = 1/4

Copy and complete this chart

Decimal Fraction

1) 0.7

2) 0.08

3) 0.42

4) 0.04

5) 0.71

6) 0.07

Classwork

Title: Glencoe Pg. 247 # 21-35

Advanced: Glencoe Pg. 247 # 27-36, 38-42

How to change percentages into fractions and decimals

A percentage is a special fraction.

The % says, “per hundred.”

For example, 47%, is simply another

way of writing the fraction 47/100

Fractions to Percents

A ratio is a comparison of 2 quantities by division. Fractions are ratios!

can be written as 34:100 in ratio form.

When a ratio compares a number to 100, it can be written as a percent.

100

34

Fractions to Percents

Ex 1: Annie answered 90 out of 100 questions correctly.

100

90Since the fraction

already has a denominator of 100, you automatically

have the percentage!

%90

Fractions to Percents

Ex 2: On average, 50.5 out of 100 students own a pet.

100

5.50Since the fraction

already has a denominator of 100, you automatically

have the percentage!

%5.50

Fractions to Percents

20

3

Find an equivalent fraction that has a

denominator of 100

%15

20

3

100

xx5

x5

100

15

Ex 3: Write as a percent.

Try These

20

17 %85100

xx5

x5

100

85

5

3 %60100

x

x20

x20

100

60

25

2 %8100

x

x4

x4

100

8

You can almost see the 100 in the percentage sign

The 1The

zeros

Percentage Fraction

7% 7/100

19% 19/100

83% 83/100

Etc.

24% = 24/100 12/50 6/25

So to write a percentage as a fraction, you simply put it

over 100 like this:

Yes, but remember to write the fraction in its

simplest form

24% = 24/100

Copy and complete this chart

Percentage Fraction Percentage Fraction

1. 23% 23/100 7. 80%

2. 24% 8. 84%

3. 55% 9. 12%

4. 20% 1/5 10. 48%

5. 17% 11. 71%

6. 78% 12. 36%

Classwork

Glencoe Pg. 252 # 13-29, 34-36

Advanced: Glencoe Pg. 252 # 10-33 even, 37-40, 42, 43

So, to change a percentage into a decimal, you always divide by

100

For example, 35% as a fraction is 35/100 so to change this into a decimal, you divide 35 by

100

35% 0.35÷ 100

To change decimal into a percentage

Decimal

PercentageTo change a decimal into a percentage, you X by 100

0.23 23%X 100

You Should Know

A a percentage is a special fraction.

23% = 23/100

Percentage to a

decimal

÷ 100

Decimal to a

percentage

X 100

Copy and complete this chart

Percentage Decimal Decimal Percentage

1. 27% 7. 0.87

2. 2% 8. 0.08

3. 55% 9. 0.42

4. 5% 10. 0.04

5. 17% 11. 0.71

6. 98% 12. 0.07