Multiplying Fractions

By: Greg StarkEC&I 831

Multiplying Fractions

Numerator--------------------Denominator Represents the number of parts into

which the whole has been divided

Represents the number of partsof a whole we have.

To multiply fractions together, we perform 3 steps:

1. Multiply the factors numerators together to form the numerator of the product

2. Multiply the factors denominators together to form the denominator of the product

3. Reduce the product into lowest terms

Multiplying Fractions

14

1

3x

For example:

= =1 x 1

4 x 3

112

Translation: what is 1/3 of 1/4

Multiplying Fractions

23

3

15x

Another example:

= =2 x 3

3 x 156

45

Translation: what is 3/15 of 2/3

645

÷ 3----

÷ 3=

215

Multiplying Fractions

37

14

15x

One more example:

= =3 x 14

7 x 15

42105

Translation: what is 14/15 of 3/7

42105

÷ 21----

÷ 21=

25

“Cancelling”It is possible to reduce fractions before you multiply by dividing out the common factors in the numerators and the denominators of the factors

37

1415

x = =1 x 21 x 5

25

Remember: the common factors must exist in both the numerator and the denominator to be reduced out

÷ 3

÷ 3

÷ 7

÷ 7

1

5

2

\1

\\\

“Cancelling”Another example

910

1524

x = =3 x 32 x 8

916

Remember: the common factors must exist in both the numerator and the denominator to be reduced out

÷ 3

÷ 3

÷ 5

÷ 5

3

8

3

\2

\\\

Review: multiplying fractions

1. Multiply the factors numerators together to form the numerator of the product

2. Multiply the factors denominators together to form the denominator of the product

3. Reduce the product into lowest terms. You may reduce factors before multiplying if the factor exists in both the numerator and the denominator

To multiply fractions together, we perform 3 steps: