Fraction Rules
What is a strategy to simplify fractions? What do we use?
Use multiplication facts or 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?
Use the "C" method. Multiply the denominator with the whole number and add the numerator.
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
1/10
What is the first rule in dividing fractions?
Keep fraction the same.
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
What fraction do we flip?
the second fraction