Multi-Part

Lesson Add and Subtract Fractions

PART A BCDE

Multi-Part

Lesson

Get ConnectED

2

GLE 0706.2.2

Understand and work with

the properties of and

operations on the system of

rational numbers.

SPI 0706.2.1 Simplify

numerical expressions

involving rational numbers.

Also addresses SPI 0706.2.3.

Main Idea

Add and subtract

fractions with like

denominators.

Vocabulary

like fractions

Add and Subtract Like Fractions

SHOES Sean surveyed ten classmates

Shoe Type Number

Cross Trainer 5

3

2

Running

High Top

to find which type of tennis shoe they like

to wear.

1. What fraction liked cross trainers?
   high tops?


2. What fraction likes either
   cross trainers or high tops?

Fractions that have the same denominators are called like fractions.

Add and Subtract Like Fractions

Words To add or subtract like fractions, add or subtract the

numerators and write the result over the denominator.

Examples Numbers Algebra

_^5

10

+ _^2

10

= _^5 +^2

10

or _^7

10

_a

c

+ _b

c

= _a + b

c

, where c ≠ 0

_^11

12

• ^4
  12
  = ^11 -^4
  12
  or _^7
  12
  _a
  c
  
  
  • _b
    c
  
  
  
  

= _a - b

c

, where c ≠ 0

Add Like Fractions

Add. Write in simplest form.

_^5

9

+ _^2

9

0 19 29 39 49 59 69 79 89 1

5

9

2

9

_^5

9

+ _^2

9

= _^5 +^2

9

Add the numerators.

= _^7

9

Simplify.

• _^3
  5
  
  
  • (- _^1
    5
  
  
  
  

(^) )

-^45 -^35 -^25 -^150

3

• 5
  1


• 5


• _^3
  5

• (- _^1
  5

(^) ) = - _^3
5

• 
  
  
  
  • 
    

    _^1
    5

    
    
  
  
  
  

• 3 + (-1)
  _
  5
  Add the numerators.

= _-^4

5

or - _^4

5

Use the rules for adding integers.

a. _^13 + _^2

3

b. - _^3

7

+ _^1

7

c. - _^2

5

+ (- _^2

5

(^) )
tofind
Lesson 2A Add and Subtract Fractions 139
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139_156_C3L2_895130.indd 139 12/31/09 12:36 PM