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CHAPTER 1 Introductory Information and Review University of Houston Department of Mathematics 36 Section 1.3: Fractions Greatest Common Divisor and Least Common Multiple Addition and Subtraction of Fractions Multiplication and Division of Fractions Greatest Common Divisor and Least Common Multiple Greatest Common Divisor:
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Page 1: Greatest Common Divisor and Least Common Multiple - · PDF file · 2011-11-02Greatest Common Divisor and Least Common Multiple ... 3. 7 and 10 4. 12 and 15 5. 14 and 28 6. 6 and 22

CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 36

Section 1.3: Fractions

Greatest Common Divisor and Least Common Multiple

Addition and Subtraction of Fractions

Multiplication and Division of Fractions

Greatest Common Divisor and Least Common Multiple

Greatest Common Divisor:

Page 2: Greatest Common Divisor and Least Common Multiple - · PDF file · 2011-11-02Greatest Common Divisor and Least Common Multiple ... 3. 7 and 10 4. 12 and 15 5. 14 and 28 6. 6 and 22

SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 37

A Method for Finding the GCD:

Least Common Multiple:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 38

A Method for Finding the LCM:

Example:

Solution:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 39

The LCM is

Additional Example 1:

Solution:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 40

The LCM is 2 2 2 3 5 120 .

Additional Example 2:

Solution:

The LCM is 2 3 3 5 7 630 .

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 41

Additional Example 3:

Solution:

The LCM is 2 2 3 3 2 72 .

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 42

Additional Example 4:

Solution:

The LCM is 2 3 3 2 5 180 .

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 43

Addition and Subtraction of Fractions

Addition and Subtraction of Fractions with Like Denominators:

a b a b

c c c

and

a b a b

c c c

Example:

Solution:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 44

Addition and Subtraction of Fractions with Unlike

Denominators:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 45

Example:

Solution:

Additional Example 1:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 46

Solution:

Additional Example 2:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 47

Solution:

Additional Example 3:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 48

Solution:

(b) We must rewrite the given fractions so that they have a common denominator.

Find the LCM of the denominators 14 and 21 to find the least common denominator.

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 49

Additional Example 4:

Solution:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 50

Multiplication and Division of Fractions

Multiplication of Fractions:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 51

Example:

Solution:

Division of Fractions:

Example:

Solution:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 52

Additional Example 1:

Solution:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 53

Additional Example 2:

Solution:

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CHAPTER 1 Introductory Information and Review

University of Houston Department of Mathematics 54

Additional Example 3:

Solution:

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SECTION 1.3 Fractions

MATH 1300 Fundamentals of Mathematics 55

Additional Example 4:

Solution:

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Exercise Set 1.3: Fractions

University of Houston Department of Mathematics 56

For each of the following groups of numbers,

(a) Find their GCD (greatest common divisor).

(b) Find their LCM (least common multiple).

1. 6 and 8

2. 4 and 5

3. 7 and 10

4. 12 and 15

5. 14 and 28

6. 6 and 22

7. 8 and 20

8. 9 and 18

9. 18 and 30

10. 60 and 210

11. 16, 20, and 24

12. 15, 21, and 27

Change each of the following improper fractions to a

mixed number.

13. (a) 97

(b) 23

5 (c)

19

3

14. (a) 103

(b) 17

6 (c)

49

9

15. (a) 274

(b) 32

11 (c)

73

10

16. (a) 1513

(b) 43

8 (c)

57

7

Change each of the following mixed numbers to an

improper fraction.

17. (a) 16

5 (b) 49

7 (c) 23

8

18. (a) 12

3 (b) 78

10 (c) 35

6

19. (a) 57

2 (b) 23

5 (c) 14

12

20. (a) 19

4 (b) 45

11 (c) 37

9

Evaluate the following. Write all answers in simplest

form. (If the answer is a mixed number/improper

fraction, then write the answer as a mixed number.)

21. (a) 2 17 7 (b)

8 4 3

11 11 11

22. (a) 3 1

5 5 (b)

4 5 2

9 9 9

23. (a) 4 15 5

8 2 (b) 7 23

3 3

24. (a) 3 21

5 5 (b) 6 2

11 117 5

25. (a) 3 14 4

5 2 (b) 3 45 5

6 7

26. (a) 5 37 7

9 2 (b) 511

4

27. (a) 23

7 (b) 3 910 10

7 3

28. (a) 7 1112 12

6 2 (b) 516 6

8 2

Evaluate the following. Write all answers in simplest

form. (If the answer is a mixed number/improper

fraction, then write the answer as a mixed number.)

29. (a) 1 1

4 2 (b)

1 1

3 7

30. (a) 1 1

8 10 (b)

1 1

6 5

31. (a) 1 1 1

4 5 6 (b)

2 3

7 5

32. (a) 1 1 1

2 7 5 (b)

4 3

11 7

33. (a) 1 1

35 10 (b)

3 5

4 6

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Exercise Set 1.3: Fractions

MATH 1300 Fundamentals of Mathematics 57

34. (a) 1 1

6 24 (b)

8 7

15 12

35. (a) 3 17 6

4 5 (b) 7 110 2

7 5

36. (a) 5 17 4

10 3 (b) 3112 8

6 4

37. (a) 3 45 7

7 8 (b) 4 29 3

5 1

38. (a) 514 6

7 3 (b) 7 138 24

2 9

39. (a) 7215 12

5 2 (b) 7 516 6

9 2

40. (a) 9 510 8

7 6 (b) 5 314 4

11

Evaluate the following. Write all answers in simplest

form. (If the answer is a mixed number/improper

fraction, then write the answer as an improper

fraction.)

41. (a) 2 3

9 4 (b)

4 8

15 9

42. (a) 7 9

16 10 (b)

11 17

14 35

43. (a) 13

5 (b) 23

7

44. (a) 25

9 (b) 27

6

Evaluate the following. Write all answers in simplest

form. (If the answer is a mixed number/improper

fraction, then write the answer as an improper

fraction.)

45. (a) 1

53 (b)

521

6 (c)

516

4

46. (a) 3

87 (b)

124

18 (c)

1125

10

47. (a) 1 25

7 11 (b)

10 9

21 8

(c)

3 16

20 15

48. (a) 36 1

25 8

(b) 8 7

19 3 (c)

1 42

14 5

49. (a) 1

520

(b) 8

43 (c)

75

10

50. (a) 3

611

(b) 8

205

(c)

422

9

51. (a) 12 18

35 7 (b)

35

59

(c)

15 5

16 24

52. (a)

14

516

(b) 36 9

5 50 (c)

49 35

24 32

Evaluate the following. Write all answers in simplest

form. (If the answer is a mixed number/improper

fraction, then write the answer as a mixed number.)

53. (a) 1045 77

8 (b) 7 98 10

1

54. (a) 329 4

2 (b) 7 416 5

3

55. (a) 1 1732 5 (b) 3 3

5 116 2

56. (a) 1 17 4

3 5 (b) 3 115 1225

57. (a) 5 18 4

5 2 (b) 1719 18

11 1

58. (a) 545 7

4 1 (b) 5 111 22

2 2