Fraction Rules
How do you multiply fractions?
Multiply the denominator (bottom)
2/3 * 4/5
8/15
1 1/2 * 5
15/2 or 7 1/2
What is the reciprocal of
11/8
8/11
How do we change a whole number into a fraction?
Put a 1 in the denominator, or put it over 1.
3/5 * 7/8
21/40
5/6 * 1 1/3
10/9 or 1 1/9
3/8 -: 2/3
9/16
When dividing fractions, what trick do we use?
Keep. Change. Flip.
4 * 7/8
7/2 or 3 1/2
3 1/3 * 1/4
5/6
6 -: 5/8
48/5 or 9 3/5
When dividing fractions, you are changing into ______________________ fractions?
multiplying
5/12 * 9
15/4 or 3 3/4
1 1/3 * 2 1/8
17/6 or 2 5/6
1/2 -: 5/8
4/5
What should you do first to mixed numbers when multiplying fractions to make it easier?
Convert them to improper fractions.
2/9 * 3/8
1/12
2 2/3 * 5 1/4
14
3/8 -: 7/12
9/14