Multiply by Whole Numbers
What is the product of 0.9 x 7?
6.3
5.6 x 10
56
0.2 x 0.3
0.06
A student says:
0.5 x 4 = 0.20
What did the student do wrong?
The correct answer is 2. They did not correctly multiply 5 x 4 and place the decimal.
A pencil costs $0.75. How much would 4 pencils cost?
$3.00
What is 3.12 x 23
71.76
2.76 x 100
276
9.1 x 0.3
2.73
A student solves:
3.4 x 10 = 3.40
Is the answer correct?
No. The decimal should move 1 place to the right, so the answer is 34.
A runner runs 2.5 miles each day for 6 days. How many miles does the runner run altogether?
15 miles
What is 19.29 x 31?
567.99
18.95 x 1,000
18,950
7.12 x 0.9
6.408
A student solves:
2.5 x 0.4 = 10
What did they forget?
They forgot to count the total number of decimal places in the factors. The correct answer is 1.
A recipe calls for 0.75 cups of flour. You make the recipe 4 times. How many cups of flour do you need?
3 cups
What is 3.264 x 63?
205.632
0.015 x 1,000
15
3.8 x 4.6
17.48
A student says:
0.73 x 100 - 0.7300
Explain the mistake.
When multiplying by 100, the decimal moves 2 places to the right. The answer is 73.
A notebook costs $3.25. A store sells 12 notebooks. How much money would you spend?
$39.00
0.81 x 52
42.12
3.142 x 10 to the third power
3,142
3.68 x 2.7
9.936
A student solves:
3.68 x 2.7 - 99.36
What did they most likely forget?
They multiplied as if there were no decimals but did not correctly place the decimal in the product. The correct answer is 9.936
A piece of ribbon is 4.5 meters long. You use 0.6 of the ribbon. How many meters of ribbon did you use?
2.7 meters