1. Splash Screen

2. Five-Minute Check (over Lesson 3–3) Main Idea and Vocabulary
Example 1: Use Estimation to Solve Problems
Example 2: Use Estimation to Solve Problems
Example 3: Use Clustering
Example 4: Use Front-End Estimation
Concept Summary: Estimation Methods
Lesson Menu

3. Estimate sums and differences of decimals.
clustering
front-end estimation
Main Idea/Vocabulary

4. Use Estimation to Solve Problems
POPULATION The table below shows the population of the American colonies in Estimate the total population of North Carolina and South Carolina.
Example 1

5. Use Estimation to Solve Problems
Round each number to the nearest hundred for easier adding.
 rounds to 200.
 rounds to 100.
300
Answer: There were about 300 thousand people in North Carolina and South Carolina.
Example 1

6. 300 thousand people 400 thousand people 500 thousand people
The table below shows the population of the American colonies in Estimate the total number of people in Pennsylvania and New Hampshire in 1770.
300 thousand people
400 thousand people
500 thousand people
600 thousand people A B C D
Example 1

7. Use Estimation to Solve Problems
 rounds to 60.
– 23.4  – rounds to 20. 40
Answer: There were about 40 thousand more people in Rhode Island than in Georgia.
Example 2

8. 50 thousand people 60 thousand people 70 thousand people
The table below shows the population of the American colonies in Estimate how many more people were in Massachusetts than in Connecticut.
50 thousand people
60 thousand people
70 thousand people
80 thousand people A B C D
Example 2

9. Use Clustering
Sid feeds a vitamin-water solution to his guinea pigs. The table shows the amount of solution the guinea pigs drank over a period of four days this week. Which is the closest to the total amount of solution the guinea pigs drank?
40 ounces
60 ounces
80 ounces
100 ounces
Example 3

10. Use Clustering
Read the Item The addends are clustered around 20. Round each decimal to 20.
21.8 → 20
19.1 → 20
18.9 → 20
→ + 20 80
Example 3

11. Use Clustering
Solve the Item Multiplication is repeated addition. So, a good estimate is 4 × 20, or 80.
Answer: C
Example 3

12. During the month of February, Jonathon spent $14
During the month of February, Jonathon spent $14.78 on gasoline the first week, $15.35 on gasoline during the second week, $15.24 on gasoline during the third week, and $14.97 on gasoline during the fourth week. Which is the closest to the total amount Jonathon spent on gasoline during February?
$35
$50
$60
$100 A B C D
Example 3

13. Use Front-End Estimation
Estimate using front-end estimation. 
 Add the front digits.
60.0
Answer: Using front-end estimation, is about 60.0.
Example 4

14. Estimate 32.7 + 65.1 using front-end estimation.
90.0
100.0
110.0
120.0 A B C D
Example 4

15. Rounding Clustering Front-End Estimation
Estimation Methods
Rounding
Clustering
Front-End Estimation
Estimate by rounding each decimal to the nearest whole number that is easy for you to add or subtract mentally.
Estimate by rounding a group of close addends to the same number before adding.
Estimate by adding or subtracting the values of the digits in the front place.
Concept Summary

16. End of the Lesson
End of the Lesson

17. Five-Minute Check (over Lesson 3–3) Image Bank Math Tools
Modeling Decimals
Dividing Decimals
Modeling Decimals
Resources

18. Round 8.4302 to the nearest tenth.
(over Lesson 3-3)
Round to the nearest tenth.
8.4
8.43
8.44
8.5 A B C D
Five Minute Check 1

19. Round 9.6452 to the nearest thousandth.
(over Lesson 3-3)
Round to the nearest thousandth.
9.65
9.646
9.645
9.64 A B C D
Five Minute Check 2

20. Round 1.257 to the nearest hundredth.
(over Lesson 3-3)
Round to the nearest hundredth.
1.3
1.26
1.25
1.2 A B C D
Five Minute Check 3

21. Round 8.186172 to the nearest ten-thousandth.
(over Lesson 3-3)
Round to the nearest ten-thousandth.
8.1861
8.1862 A B C D
Five Minute Check 4

22. Round 8.239 to the nearest hundredth.
(over Lesson 3-3)
Round to the nearest hundredth.
8.2
8.23
8.24
8.3 A B C D
Five Minute Check 5

23. (over Lesson 3-3)
The average retail price of gasoline in Texas during the week of March 13, 2006 was $2.283 per gallon. Round this to the nearest cent.
$2.30
$2.29
$2.28
$2.27 A B C D
Five Minute Check 5

24. End of Custom Shows