Number and Operations in Base Ten

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Lesson 4

Hands On: Add Decimals Using Base-Ten Blocks

Homework Helper

Jessica purchased a cup of hot chocolate for $1.29 and a granola bar for $1.55. How much did it cost for both items?

Find $1.29 + $1.55. Use base-ten blocks.

Model 1.29 and 1.55.

HundredthsTenthsOnes

Combine the base-ten blocks. Since there are 14 hundredths, you need to regroup. You can regroup 14 hundredths as 1 tenth and 4 hundredths. The model shows the result.

HundredthsTenthsOnes

There are 2 ones, 8 tenths, and 4 hundreths.

So, the total for the hot chocolate and granola bar was $2.84.

Check Use estimation to check for reasonableness.

$1 + $2 = $3 and $2.84 ≈ $3

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Lesson 4 My Homework�327

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PracticeAdd. Use base-ten blocks. Draw each result in the table.

1. 1.83 + 0.36 = 2. 3.1 + 1.34 =

Problem Solving 3. Lucas had 2.3 pounds of grapes left over

from his class party. The class ate 1.9 pounds of the grapes. How many pounds of grapes did Lucas buy? Use models to find the sum.

4. 3 Justify Conclusions Janice wanted to download the following items for her cell phone: A ringtone for $3.10, a picture for $1.95 and a game for $2.05. She has $8. Not including tax, does Janice have enough money to buy all three items? Explain.

5. Kelli had $0.55 in her pocket to buy a snack after school. Renee had $1.64 in her pocket. They decided to share a snack. How much can they spend on a snack altogether? Use models.

HundredthsTenthsOnesHundredthsTenthsOnes

4.2 pounds; See students’ models.

yes; The total cost for the three items would be $7.10.

$2.19; See students’ models.

2.19 4.44

328�Chapter 5 Add and Subtract Decimals

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