Fraction Rules
What is the strategy to simplify fractions?
Divide by least common factor.
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
Multiply straight across (multiply numerators and multiply denominators)
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
All fractions are also what type of problem?
Division problem
3 word phrase to help us with dividing fractions.
Keep - Change - Flip
4 * 7/8
7/2 or 3 1/2
3 1/3 * 1/4
5/6
6 -: 1/8
48
How do we convert a mixed number into a fraction?
Multiply the denominator with the whole number and then add the numerator.
When dividing fractions, you actually end up having to _________________ the fractions.
multiply
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
What is the most important rule in adding/subtracting fractions?
Be sure the denominators are the same.
What should you do first to mixed numbers when multiplying or dividing fractions?
Convert them to improper fractions
2/9 * 3/8
1/12
2 2/3 * 5 1/4
14
1/12 -: 3
1/36
What fraction do we flip?
the second fraction