Whole Number and Decimal Multiplication

5th Grade Math Resources for families

Represent multiplication of whole numbers and decimals to the hundredths with objects/pictorial models, including area models

Multiply a three-digit by a two-digit whole number

Multiply decimals to the hundredths

Have your student estimate about how much his or her purchase will cost. He or she may round to whole numbers or use compatible numbers to help estimate. For example, 4 × 2.89 is close to 4 × 3, and 4 × 3 = 12. The total cost will be about $12. Similarly, a product can be estimated if one of the numbers has two digits. So, 16 × $3.18 is close to 15 × 3, and 15 × 3 = 45. The total cost is about $45.
Practice using partial products while doing multiplication. This can be a two-person activity with you and your child. Use easier three-digit numbers. For example, try 300 × 120. Tell your child, “You figure out 300 × 100, and I’ll figure out 300 × 20. Then we can add those two numbers together to get the result.” (300 × 100 = 30,000; 300 × 20 = 6,000; 30,000 + 6,000 = 36,000)

Using the Area Model