Dividing Fractions and Mixed Numbers

1
Dividing Fractions and Mixed Numbers

• 5.4

2
Objective

• You will be able to divide fractions and mixed
  numbers
• Word Watch
• -reciprocal

3

• To divide by a fraction, multiply by its
  reciprocal.
• Two numbers whose product is 1 are reciprocals.

2 3
3 2
The reciprocal of is
1 5
5 1
1 5

x
5
x

1
4
Dividing 8 by 2 gives the same result as
multiplying 8 by the reciprocal of 2, or
1 2

_____
_____
reciprocals
?
?
.
_
1 2
8 2 4
8 x 4
.
?
?
_____
_____
same results
5

• Dividing fractions is
• simple as pie flip the
• second number and multiply!

6
Divide by a Fraction

• Find

3 4
1 2
.
_
.
.
_
3 4
1 2
3 4
2 1
1 2

x
.
Multiply by the reciprocal of , which is 2.
?
3 4
2 1
3 x 2 4 x 1

x

6 4

Multiply
?
2 4
1 2


1
1
SIMPLIFY!!! ?
?
7
? YOUR TURN!! ?
.
2 3
5 6
_

.
5 6
3 2
Multiply by the reciprocal
x
?
5 x 3 6 x 2

15 12

3 12
1 4

1

1
8
Divide by Mixed Numbers
.

_
1 2
15
1
.
.
3 2
_
1 2
15
Rename 1 as an improper fraction
.
?
2 3
x
15

Multiply by the reciprocal
?
15 1
2 3
Rewrite whole s over 1

x
?
15 x 2 1 x 3

30 3


10
9
? YOUR TURN!! ?
1 2
.
5 7
_
6
3
.

.
13 2
26 7
_
Rename the mixed s as improper fractions
?

.
13 2
7 26

x
?
Multiply by the reciprocal
1
7 26
13 2
/
x
Simplify before multiplying

?
/
2
1 x 7 2 x 2

7 4
3 4
1


10
Thought of the day

• A snail can sleep for three years.
• zzzz.zzzzzzzzzzzzzzzz