Fraction Rules
When dividing, which fraction do we flip?
The second fraction
If the area of a rectangle is 20 squared centimeters and the width is 2 4/5 centimeters, what is the length of the rectangle?
7 1/7 cm
1 1/2 * 5
15/2 or 7 1/2
What is the reciprocal of
11/8
8/11
What is the reciprocal of
2 1/12
12/25
Before multiplying mixed numbers - what must be done?
Change mixed numbers to improper fractions.
How do we change a whole number into a fraction?
Put a 1 in the denominator, or put it over 1.
Sammy sold 5 1/3 pounds of candy for the school fundraiser. Her friend sold 3 1/4 times as much as Sammy. How many pounds of candy did her friend sell?
17 1/3 pounds
5/6 * 1 1/3
10/9 or 1 1/9
3/8 -: 2/3
9/16
2 1/8 -: 3
17/24
Before adding fractions, what has to happen?
They must have a common denominator.
3 word phrase to help us with dividing fractions.
Keep - Change - Flip
Grace and two of her friends are sharing 4/5 of a package of gum. What fraction of the package of gum will each friend receive?
4/15
3 1/3 * 1/4
5/6
6 -: 5/8
48/5 or 9 3/5
1 1/8 -: 1/10
45/4 or 11 1/4
What is the math vocabulary word for "flip it" ?
Reciprocal
When dividing fractions, you are changing ________ into ___________.
division into multiplication
Surprise Trivia Question: What is Ms. T's favorite color?
pink
1 1/3 * 2 1/8
17/6 or 2 5/6
1/2 -: 5/8
4/5
3 1/4 -: 1 1/2
13/6 or 2 1/6
Surprise Trivia question....what is the IB profile for the Month of February?
Reflection
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.
Mia is preparing rice for dinner. Each serving of rice requires 2/3 of a cup of water. If Mia is making 7 1/4 servings of rice, how much water will he need?
4 5/6 cups of water
2 2/3 * 5 1/4
14
3/8 -: 7/12
9/14
3 1/2 -: 5 2/3
21/34
What operation does the fraction bar mean?
Division