Rules
Multiplying Fractions
When multiplying two fractions, you multiply straight across. Numerator x Numerator and Denominator X Denominator.
1/3 + 5/3
2
2 1/3 - 1/4
2 1/12
1/2 x 14
7
1/2 / 1
1/2
Multiplying a whole number by a fraction
When multiplying a whole number by a fraction, you multiply the whole number and the numerator and leave the denominator unchanged.
1/4 + 3/7
19/28
9/20
2 x 3/7
6/7
3/4 / 3
1/4
Converting Mixed Numbers
To convert a mixed number to a fraction, multiply the denominator by the whole number and add the product to the numerator, leave the denominator unchanged.
3 3/4 + 1/2
4 1/4
6 1/9 - 3 /10
5 13/15
6 x 4/9
2 2/3
4/7 / 2
2/7
Dividing a fraction by a whole number
When dividing a fraction by a whole number, multiply by the reciprocal of the whole number instead
7 1/2 + 6 1/4 + 3 6/8
17 1/4
7 3/8 - 7/10
6 27/40
(1/2 x 23) + (1/2 x17)
20
1 1/2 / 3
1/3
What is a reciprocal?
When we multiply two numbers and the product is 1 they are reciprocals.
3/10 + 4/5 + 3/4
1 17/20
3 - 1/2 - 4/5
1 7/10
(1/2 x 1/2) + (3/2 X 4/5) - 1 - 3/20 - 3/10
0
1/2 / 3 / 4
1/24