Fraction Rules
What is a strategy to simplify fractions? What do we use?
Divide out the greatest 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
What are the steps for multiplying fractions?
Cross/vertically reduce. Then 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 division to ______________________ .
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
1/10
What should you try to do to fractions before you multiply them?
Vertically and cross reduce
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
A caterpillar moves along a leaf. The leaf is 1 1/3 in. long. The caterpillar travels 1/9 in. every second. How long does it take the caterpillar to move along the leaf? Show your work.
12 seconds