Multiply and Divide Fractions

PART A B CD

Get ConnectED

Multi-Part

Lesson 3

GLE 0706.2.2

Understand and work with

the properties of and

operations on the system of

rational numbers.

SPI 0706.2.3 Use rational

numbers and roots of perfect

squares/cubes to solve

contextual problems. Also

addresses GLE 0706.1.7,

SPI 0706.2.1.

160 Rational Numbers

Multiply Fractions

LUNCH Two thirds of the

students at the lunch table ordered a

hamburger for lunch. One half of those

students ordered cheeseburgers.

1. What fraction of the students
   at the lunch table ordered a
   cheeseburger?


2. How are the numerators and
   denominators of ^2
   3
   and ^1
   2
   related
   to the fraction in Exercise 1?

Multiply Fractions

Words To multiply fractions, multiply the numerators and multiply

the denominators.

Examples Numbers Algebra

_ 12 × _ 23 = _^1 2 ×× 3 2 or _ 62 _a

b

· _c

d

= _a ·^ c

b · d

or _ac

bd

, where b, d ≠ 0

Multiply Fractions

Multiply. Write in simplest form.

_^1

2

× _^1

3

_^1

2

× _^1

3

= _^1 ×^1

2 × 3

Multiply the numerators.

Multiply the denominators.

= _^1

6

Simplify.

2 × (- _^3

4

(^) )
2 × (- ^3
4
(^) ) = ^2
1
× ( -^3
4
(^) ) Write 2 as ^21 and - 43 as - 43.

2 × (-3)

1 × 4
Multiply the numerators.
Multiply the denominators.
= -^6
4
or - 1 ^1
2
Simplify.
a. ^3
5
× ^1
2
b. ^1
3
× ^3
4
c. ^2
3
× (- 4 )
Main Idea
Multiply fractions and
mixed numbers.
158_165_C3L3_895130.indd 160 12/31/09 12:40 PM