Objective 8Multiply and divide fractions

© 2002 by R. Villar

All Rights Reserved

Multiply and divide fractions

Change the mixed numbers to improper fractions, then multiply...

13

• 817

Example:

13

• 577

You can either multiply numerators by numerators, then denominators by denominators…then reduce...

= 5721

÷33

=197

=257

…or you can cross cancel and then multiply...

13

• 5771

19=

197

=257

Example:

Change division into multiplication of the reciprocal (after you change mixed numbers into improper fractions)...

7÷(−323)

=71

÷ –113

=71

• 3

−11

=−2111

=−11011

Example: This is called a complex fraction (fractions within fractions). Keep in mind that the fraction bar really means division. So the problem could be written like the following...

1−38

25

+47

(1 – 38) ÷ (

25

+ 47)

= 175272

Simplify each part inside of

the parentheses...

(88

– 38) ÷ (

35 +

35)

(58) ÷ (

3435

) Now change this to multiplication

58

• 3534

14 20