Multiply Decimals by
Powers of 10
Powers of 10
Estimate Multiplication with Decimals
Model Multiplication with Decimals
Decimals by Whole Numbers
(Mental Math)
(Mental Math)
Multiply Decimals by
Whole Numbers
Whole Numbers
100
Adam is laying ceramic tile on a kitchen floor.
Each tile costs $3.59. How much do 100 tiles cost?
$359
100
Estimate
5.95 x 3.88
5.95 x 3.88
6 x 4
About 24
100
Write an equation for the decimal multiplication model
0.8 x 0.4 = 0.32
-or-
0.4 x 0.8 = 0.32
100
8 x 0.9 =
7.2
Seven and two tenths
100
83.5 x 6
83.5 x 6 = 501.0
200
A packet of ketchup has 0.45 fluid ounces of liquid. How much liquid is in 102 packets of ketchup
45 fl oz
200
Jeremiah buys 42 Air Heads that cost $0.19 each.
What is the best estimate for how much his total is?
40 x $0.20 = $8.00
His total is about $8.00
200
Write an equation for the decimal multiplication model
0.2 x 0.5 = 0.10 = 0.1
-or-
0.5 x 0.2 = 0.10 = 0.1
200
0.6 x 0.03 =
0.018
Eighteen Thousandths
200
Levi buys 42 Air Heads that cost $0.19 each.
What is his actual total?
$7.98
300
What power of 10 makes the equation true?
0.305 x ___ = 3,050
104
300
Estimate
0.5 x 41.07
0.5 x41.07
0.5 x 40
"1/2 of 40"
About 20
300
Write an equation for the multiplication decimal model shown
0.2 x 0.3 = 0.06
300
80 x 0.4 =
80 x 0.4 = 32.0 = 32
300
One gallon of milk has 128 fluid ounces. How much milk is in 8.5 gallons?
1,088 fl oz
400
Savannah bought seashells from the souvenir shop when she was on vacation. Each seashell cost $0.85
How much would it be if she wanted to buy 10 seashells?
How much would it be if she wanted to buy 100 seashells?
10 for $8.50
100 for $85
400
Estimate
389.945 x 38.894
389.945 x 38.894
400 x 40
About 16,000
400
Write an equation for the decimal model shown
0.7 x 0.4 = 0.28
-or-
0.4 x 0.7 = 0.28
400
1.2 x 0.4
0.48
400
46.9 x 30 =
46.9 x 30 = 1,407.0
500
The decimal point moves ________ spot to the _______ for every power of 10.
The decimal point moves ONE spot to the RIGHT for every power of 10.
500
Without doing the multiplication, drag the numbers to match each expression with its product.
Use estimation and number sense to help you.
20.397 11.04 49.9125
9.2 x 1.2
5.23 x 3.9
6.05 x 8.25
9.2 x 1.2 = 11.04
9x1=9
5.23 x 3.9 = 20.397
5x4=20
6.05 x 8.25 = 49.9125
6x8=48
500
Write an equation for the decimal model shown
0.6 times 1.5 = 0.9
or
1.5 times 0.6 = 0.9
500
900 x 0.01 =
900 x 0.01 = 9.00
500
2.73 x 44 =
2.73 x 44 = 120.12