What was the combined time for the first two legs of the relay race? Choose an Operation Add to join groups.
Find 21.49 + 21.59.
Estimate: 21 + 22 = 43

Guided Practice*

Do you know HOW?
In 1 through 6, add the decimals.

Question 1.
0.82 + 4.21

Question 2.
9.1 + 7.21

Question 3.
9.7 + 0.24

Question 4.
3.28 + 6.09

Question 5.
0.26 + 8.3

Question 6.
4.98 + 3.02

Do you UNDERSTAND?

Question 7.
Reasonableness How do you know the total time for the first two legs of the race is reasonable?

Question 8.
Writing to Explain How is finding $4.25 +$3.50 like finding 4.25 + 3.5? How is it different?

Independent Practice

In 9 through 26, add the decimals.

Question 9. Question 10. Question 11. Question 12. Question 13. Question 14. Question 15. Question 16. Question 17. Question 18. Question 19. Question 20. Question 21.
$271.90 +$34.22 22.

Question 22.
658.2 + 0

Question 23.
0.922 + 6.4

Question 24.
8.02 + 9.07

Question 25.
13.9 + 0.16

Question 26.
0.868 + 15.973

Step 1

Write the numbers. Line up the decimal points. Step 2

First, add the hundredths. Regroup if necessary Step 3

Add the tenths, ones, and tens. The decimal point in the sum is aligned with the decimal point in the addends. Check the sum with your estimate. The total time for the first two legs of the race was 43.08 seconds.

Problem Solving

Question 27.
A balloon mural of the Chicago skyline measures 17.6 m on two sides and 26.21 m on the other two sides. What is the perimeter of the mural?
A. 38.81 m
B. 48.21 m
C. 55.74 m
D. 87.62 m

Question 28.
Writing to Explain Juan adds 3.8 ± 4.6 and gets a sum of 84. Is his answer correct? Tell how you know.

Question 29.
Jamie earned $27 taking care of a neighbor’s dog for one week. She spent$19.95 on a new DVD. Later, she earned $15 for raking leaves. Which expression shows how to find the money Jamie has left? A.$27 + $19.95 +$15
B. $19.95 –$15 + $27 C.$27 – $19.95 –$15
D. $27 –$19.95 – $15 Answer: Question 30. At a flower shop, Teri sees that roses are$3 each, carnations are $4 for 3 flowers, and tulips are$4 for 4 flowers. She buys 3 roses and
3 carnations. She has \$20. How much change does Teri get back?

Question 31.
Which two cities had the greatest combined rainfall for the period given?
A. Caribou and Boise
B. Springfield and Macon
C. Macon and Boise
D. Caribou and Springfield 