Dividing Fractions

By: Greg Stark

Division• A basic rule of math – if you multiply the dividend

(the number being divided) and the divisor (the number you are dividing by) by the same factor, the answer will not change

2÷ =4 2

2÷ =4 24÷8=X 2 X 2

2÷ =4 210÷20=X 5 X 5

Division• What is the easiest number to divide by?• A basis rule of math – dividing by 1 does not change

the value of number

1÷ =4 4

1÷ =2 21÷ =326 326

Division by a Fraction• How can we use this information to divide by one?• A basic rule of math – if we multiply a number by it’s

inverse, the product is one

÷ x

=

34

14 ÷

34

14

41

41

x\÷ 4

÷ 4\

1

1

1

1÷ 4

÷ 4

\\

÷31

11

1÷3 3=

÷ 7271

Dividing a Fraction by a Fraction

• Another example:

÷ x

=

23

27 ÷

23

72

72

x\÷ 2

÷ 2\

1

1

1

1÷ 2

÷ 2

\\

73 2 1

3

\\ ÷ 7

1

Dividing a Whole Number by a Fraction

• For example:

÷ x

=

12 ÷

51

12

21

21

x\÷ 2

÷ 2\

1

1

101 10

5

Dividing Mixed Numbers• In order to divide with fractions, both factors must be

in the form of fractions• To convert a mixed number into a fraction, multiply

the whole number by the denominator of the fraction, then add the product to the numerator

4 ÷ = ==123

15

53

215

6325

13252÷

35

215 x =

Review: Dividing with fractions1. Ensure all values are fractions, before you beginning the division process2. To convert a whole number to a fraction, place it over 1.3. To convert a mixed number to a fraction, multiply the whole number by the

denominator of the fraction, then add the product to the numerator 4. Invert the divisor - the fraction you are dividing by – and multiply the fractions

together5. Reduce the product to lowest terms