How to Multiply Fractions

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Multiplying fractions is actually pretty easy, and the rules are simple.

Rule

Multiplying Fraction by Fraction

a b c d = ac bd

Multiplying a fraction by another fraction and multiplying a fraction by an integer are two of the easiest operations you will learn. That’s really fun! When multiplying a fraction by another fraction, you simply multiply numerator by numerator and denominator by denominator.

When you multiply a fraction by an integer, you just multiply the integer by the numerator. This works because you can rewrite the integer as a fraction with 1 as its denominator. From there you simply multiply numerator by numerator and denominator by denominator.

Formula

Multiplying Fraction by a Number

a b c = ac b ,

because

a b c = a b c 1 = a c b 1 = ac b .

Example 1

Find 3 5 2 7.

3 5 2 7 = 3 2 5 7 = 6 35

Find 4 3 5.

4 3 5 = 4 3 5 1 = 4 5 3 1 = 20 3

Find 1 6 5 3.

1 6 5 3 = 1 5 6 3 = 5 18

Find 7 3 5.

7 3 5 = 7 1 3 5 = 7 3 1 5 = 21 5

The math master cutting paper into squares with scissors

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