Multiplication Strategies
Evaluate 6 x (15 x 2)
180
Evaluate (8 x 3) x 4
24 x 4
= 96
A rectangular prism is 4 units long, 3 units wide, 2 units high. What is the volume of the prism unit cubes?
V3 = L x W x H
24 units 3
Four friends earned $80 selling their old toys. They want to split their earnings evenly. How much will each friend get?
$80 / 4 friends
= $20 each
Solve the following expression to determine if it is TRUE or FALSE. Show your work.
(3 x 8) x 5 = 3 x (8 x 5)
(3 x 8) x 5 = 3 x (8 x 5)
24 x 5 = 3 x 40
120 = 120
TRUE.
Fill in the blank: ____ x 9 = 24 x 18
48
Write an equation to represent the following statement. Then solve.
To find 42 x 9, multiply by 10 and subtract one group of 42.
42 x (10 - 1)
(42 x 10) - (42 x 1)
420 - 42
= 378
A box is 5 units long, 4 units wide, and 6 units high. Write an equation, then solve to find the volume of the box in units cubed.
5 x 4 x 6 = 120 units 3
There are 128 parents carpooling to an away football game. If each bus carries 30 people, how many buses will they need to get to the game?
128 / 30
= 4 r 8
so they need 5 buses
Fill in the blank. 150 x 12 = ____ x 6
300
Use the DISTRIBUTIVE property to solve: 54 x 19
DO NOT USE THE STANDARD ALGORITHM OR BOX METHOD!
54 x (20 - 1)
(54 x 20) - (54 x 1)
1,080 - 54
= 1,026
Evaluate (90 x 14) - (20 x 14)
1,260 - 280
= 980
One layer of a rectangular prism has 28 cubes. If there are 9 layers, how many cubes are in the rectangular prism?
28 x 9
= 271 cubes
A sports store just got a shipment of 504 brand new soccer balls. If there are 42 soccer balls in each box, how many boxes of soccer balls did the store get?
504 / 42
= 12 boxes
EXPLAIN why this expression is true or false.
** HINT: what property are they using to solve?
46 x 15 = (40 x 15) + (6 x 15)
It is TRUE because you can use the DISTRIBUTIVE property to solve multiplication problems easier. When you use the distributive property, you break apart one of the factors, and multiply both of those numbers by the other factor, and add. This makes it easier to solve.
Solve by doubling and halving:
48 x 25
24 x 50
= 1,200
Write an solve an equation for the following statement:
Find 16 x 34 by finding 10 x 34 and adding 6 x 34.
16 x 34
(10 x 34) + (6 x 34)
340 + 204
= 544
Write a numerical expression for the volume of a prism with a base of 16 x 3 and a height of 8. Then solve.
16 x 3 x 8
16 x 24
(16 x 20) + (16 x 4)
320 + 64
= 384 units 3
A theatre has 276 guests coming to see a show. If each row seats 18 people, how many rows are needed?
276 / 18
= 15 r 6
so they need 16 rows
Fill in the blank to make the statement true.
82 x 29 = (30 x 82) - (____ x 82)
1
Explain how you can use the distributive property to solve 63 x 49. Use numbers or words to explain your thinking. Then solve using the distributive property.
63 x (50 - 1)
(63 x 50) - (63 x 1)
3,150 - 63
= 3,087
Write a numerical expression for the following statement, then solve.
To find 18 x 25, I double one factor and halve theater.
18 x 25
9 x 50
= 450
A storage box holds 34 cubes in each layer and has 12 layers. Write an equation to find the total number of cubes. Then solve.
34 x 12
(34 x 10) + (34 x 2)
340 + 68
= 408 cubes
A box holds 648 markers. Each layer in the box has 27 markers. How many layers of markers are there?
648 / 27
= 24
Use TWO different multiplication strategies to solve the following problem: 36 x 25
** HINT: you can use doubling & halving, and the distributive (break apart) strategies.
Strategy 1: DOUBLING & HALVING
36 x 25 --> 18 x 50 = 900
Strategy 2: DISTRIBUTIVE (BREAK- APART)
36 x 25 --> (25 x 30) + (25 x 6) --> 750 + 150
=900