Fraction Rules
When we multiply fractions we multiply...
straight across!
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
A scientist had 3/4 of a bottle of solution. She used 1/6 of the solution in an experiment. How much of the bottle did she use?
1/8
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
1/8 -: 3
1/24
Dan has 4 cartons of juice. He pours 1/8 carton for each person on a camping trip. How many people can he serve?
32
How do you change an improper fraction to a mixed number?
4 * 7/8
7/2 or 3 1/2
3 1/3 * 1/4
5/6
6 -: 1/8
48
Find the area of a rectangle with side lengths 5/3 feet and 3/4 foot.
A= 1 1/4 feet2
Multiply the whole number and denominator and then add the numerator to get a new numerator. Keep the same denominator
5/12 * 9
15/4 or 3 3/4
1 1/3 * 2 1/8
17/6 or 2 5/6
1/2 -: 5
1/10
Jenna ran 2 7/8 kilometers each day for a week. How far did she run in all?
20 1/8 kilometers
What should you do first to mixed numbers when multiplying or dividing fractions?
Convert them to improper fractions.
Change them to improper fractions.
Make them improper fractionns.
2/9 * 3/8
1/12
2 2/3 * 5 1/4
14
1/12 -: 3
1/36
George stretched his taffy to 3 1/3 feet. Maria stretched her taffy 2 3/4 times as much as George. How far did Maria stretch her taffy?
9 1/6 feet