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
3/8 -: 2/3
9/16
All fractions are also what type of problem?
Division problem
What do we think when dividing an improper fraction?
The denominator x what number is close to the numerator without going over?
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
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 using your _______________ facts.
multiplication
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 is the first rule in dividing fractions?
Keep fraction the same.
What should you do to mixed numbers before multiplying or dividing fractions?
Convert them to improper fractions before multiplying the fractions
2/9 * 3/8
1/12
2 2/3 * 5 1/4
14
3/8 -: 7/12
9/14
What fraction do we flip?
the second fraction