1. Splash Screen

2. Add and Subtract Decimals
Five-Minute Check (over Lesson 2–5)
Main Idea
Example 1: Add Decimals
Example 2: Annex Zeros
Add and Subtract Decimals
Lesson Menu

3. I will add and subtract decimals through thousandths.
Main Idea/Vocabulary

4. Add Decimals
The members of the Crawford household consume 39.2 gallons of milk per year. The Ramirez family consumes 54.6 gallons of milk per year. How many gallons of milk do the two families consume in all?
Estimate = 94
Example 1

5. Line up the decimal points. Step 2 Add as with whole numbers. Step 3
Add Decimals
Step 1
Line up the decimal points.
Step 2
Add as with whole numbers.
Step 3
Bring the decimal point straight down in the sum.
39.2
54.6 +
39.2
54.6 +
39.2 8 3 9 +
54.6 9 3 8 .
Answer: So, the two families consume 93.8 gallons of milk. This is close to the estimate, so your answer is reasonable.
Example 1

6. Find
8.97
89.7
89.6
88.6 A B C D
Example 1

7. Annex Zeros Find 52.1 – 29.31. Estimate 52.1 – 29.31 52 – 29 = 23
Step 1 Line up the decimal points. Annex a zero so that both numbers have the same place value.
52.1
– 29.31
Example 2

8. Step 3 Bring the decimal point straight down in the difference. 52.10
Annex Zeros
Step 2 Subtract as with whole numbers, from right to left. Regroup if necessary. 11 10 4 1 10
52.10
– 29.31 2 2 7 9
Step 3 Bring the decimal point straight down in the difference.
52.10
– 29.31 9 7 2 .
Answer: The difference is
Since is close to the estimate, the answer is reasonable.
Example 2

9. Find 75.2 – 48.3. A B C D A B C D
Example 2

10. End of the Lesson
End Lesson

11. Five-Minute Check (over Lesson 2–5) Image Bank Math Tool Chest
Add and Subtract Decimals
Resources

12. (over Lesson 2–5)
Determine whether you need an estimate or an exact answer. Then solve the problem. Skah has $25 to spend. He wants to buy four books that cost $5.95 each. Does he have enough money?
exact answer; no
estimate; no
exact answer; yes
estimate; yes A B C D
Five Minute Check 1

13. End of Custom Shows