Multiplying Fractions
True/False: You need to find a common denominator before multiplying fractions.
False
Explain how to convert a mixed number to an improper fraction.
Multiply the denominator by the whole number; add to the numerator.
(Denominator stays the same, numerator changes, no wholes.)
What is the acronym used for dividing fractions? What does it stand for?
KSR: Keep, Switch, Reciprocal
What does "of" typically indicate?
Multiplication
If there is no amount given for starting total, what do we use?
1 whole
2/3 x 6 =
4
Explain how to convert an improper fraction to a mixed number.
Find the highest multiple of the denominator that is less than or equal to the numerator. The number of multiples is the whole number, and any remaining is the numerator. (Denominator stays the same.)
1/3 ➗ 4 =
1/12
What does "into" typically indicate?
Find the remainder by subtracting from the starting total (amount given or 1 whole). Then, multiply that remainder by the fraction.
5/9
1 2/3 x 1/6 =
5/18
3 ➗ 1/5 =
15
Noa has 3/4 kilogram of flour. She uses 6/7 of it to bake some Challah. How much flour did she use?
3/4 x 6/7 = 9/14
What is a possible word problem for the following equation: 2 2/3 ➗ 7.
a) Mr. Bean has 2 2/3 liters of tea. He pours it equally into 7 cups.
b) Ms. Costas spends 2 2/3 hours playing with her cat every day this week.
c) Ms. Udell has 7 pieces of chocolate. She gives away 2 2/3 pieces.
A
7/2 x 1/3 =
7/6 = 1 1/6
3 4/5 x 2/19 =
2/5
2 1/2 ➗ 7/2 =
5/7
Ms. Costas brews 2/3 gallons of coffee. She gives 1/2 of it to Mrs. Udell. Then, she pours equal parts of the remaining coffee into 4 mugs. What fraction of a gallon is in each mug?
1/12 gallon
Mr. German buys 8 bags of kinetic sand. Each bag of sand weighs 2 3/8 pounds.
What is the total weight of the sand that Mr. German buys?
8 x 2 3/8 = 8 x 19/8 = 19
9/4 x 2/3 =
3/2 = 1 1/2
1 1/3 x 2 1/3 =
28/9 = 3 1/9
4 1/2 ➗ 2 1/4 =
2
Coach Ricky bought a new mat measuring 3 1/3 meters by 3 2/5 meters. The mat costs $9 per square meter. How much did Coach Ricky pay for the mat?
10/3 x 17/5 = 34/3
34/3 x 9 = 34 x 3 = 102
Ms. Costas spends 1/4 of her spending money on clothes. She then spends 3/5 of her remaining money on cat toys for Bean. If she has $27 left, how much spending money did she start with?
1 - 1/4 = 3/4
3/4 x 3/5 = 9/20
3/4 - 9/20 = 15/20 - 9/20 = 6/20 = 3/10
3/10 = $27
1/10 = $9
10/10 = $90
She started with $90