7th Grade Math

Chapter Study Guide and Review

192 Rational Numbers

Add and Subtract Fractions (continued)

Add and Subtract Mixed Numbers (Lesson 2D)

Add or subtract. Write in simplest form.

25. 
    
    
    
    • 3 152 + 6 159 26. 4 ^13 - 2 ^23
    
    
    
    


26. 7 53 - 5 31 28. 5 43 - (- 1 61 )


27. BABYSITTING Lucas watched his little
    sister for 2 1 2 hours on Friday, 3 ^23 hours
    on Saturday, and 1 _^34 hours on Sunday.
    For how many hours did Lucas watch
    his little sister?

EXAMPLE 5 Find 4 _^1

5 -^2

_^3

5.

4 _ 51 - 2 _^35 = 3 _^65 - 2 _ 53 Rename 4 _ 51 as 3 _ 56.

= 1 _^35 Subtract the whole numbers and

subtract the fractions.

Lesson 2

Multiply and Divide Fractions

Multiply Fractions (Lessons 3A and 3B)

Multiply. Write in simplest form.

30. ^3
    5
    × ^10
    21
    31. 4 × (- _^13
    20

(^) )

32. 2 ^1
    3
    × ^3
    4
    33. 4 ^1
    2
    × 2 ^1
    12


33. FOOD An average slice of American
    cheese is about 1 _ 8 -inch thick. What is
    the height in simplest form of a package
    containing 20 slices?

EXAMPLE 6 Find 3 _^1

2

× 2 _^3

4

.

3 _^1

2

× 2 _^3

4

= _^7

2

× _^11

4

Rename 3 _^12 and 2 _^34.

= _^7 ×^11

2 × 4

Multiply the numerators and

multiply the denominators.

= _^77

8

or 9 _^5

8

Simplify.

PSI: Draw A Diagram (Lesson 3C)

35. COOKIES A cookie jar contains three
    types of cookies: oatmeal, chocolate chip,
    and sugar. Sixty percent are chocolate
    chip. Half of the remaining cookies are
    oatmeal. If there are 9 oatmeal cookies,
    how many cookies are in the jar? Use the
    draw a diagram strategy.

EXAMPLE 7 Marian is painting a fence

that is 72 feet long. She has already painted

_^58 of the fence. How many feet of fence does

she have left to paint?

Make a bar diagram.

72 feet

finished

99999999

So, she has 3 × 9 or 27 feet of the fence left

to paint.

Lesson 3

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