Math worksheet for estimating sums and differences with subtraction exercises.

The image you uploaded appears to be a worksheet titled "Independent Practice 2: Estimate Sums and Differences." The task involves estimating sums and differences of given numbers. Below is a detailed explanation of how to solve such problems, along with the solutions for the provided examples.

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Understanding the Task

The goal is to estimate the sum or difference of two numbers by rounding them to the nearest ten or hundred (depending on the context). This simplifies calculations and provides an approximate result.

#### Steps to Solve:
1. Identify the Numbers: Look at the two numbers given in each problem.
2. Round Each Number: Round each number to the nearest ten or hundred.
3. Perform the Operation: Add or subtract the rounded numbers to get the estimated result.
4. Write the Answer: Provide the estimated sum or difference.

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Solutions for the Problems

#### Problem 1:
- Numbers: 87 and 99
- Rounding:
- 87 rounds to 90 (nearest ten)
- 99 rounds to 100 (nearest ten)
- Sum: \( 90 + 100 = 190 \)
- Answer: 190

#### Problem 2:
- Numbers: 99 and 61
- Rounding:
- 99 rounds to 100 (nearest ten)
- 61 rounds to 60 (nearest ten)
- Sum: \( 100 + 60 = 160 \)
- Answer: 160

#### Problem 3:
- Numbers: 61 and 48
- Rounding:
- 61 rounds to 60 (nearest ten)
- 48 rounds to 50 (nearest ten)
- Difference: \( 60 - 50 = 10 \)
- Answer: 10

#### Problem 4:
- Numbers: 48 and 85
- Rounding:
- 48 rounds to 50 (nearest ten)
- 85 rounds to 90 (nearest ten)
- Sum: \( 50 + 90 = 140 \)
- Answer: 140

#### Problem 5:
- Numbers: 79 and 64
- Rounding:
- 79 rounds to 80 (nearest ten)
- 64 rounds to 60 (nearest ten)
- Sum: \( 80 + 60 = 140 \)
- Answer: 140

#### Problem 6:
- Numbers: 64 and 7
- Rounding:
- 64 rounds to 60 (nearest ten)
- 7 rounds to 10 (nearest ten)
- Sum: \( 60 + 10 = 70 \)
- Answer: 70

#### Problem 7:
- Numbers: 7 and 48
- Rounding:
- 7 rounds to 10 (nearest ten)
- 48 rounds to 50 (nearest ten)
- Difference: \( 10 - 50 = -40 \)
- Answer: -40

#### Problem 8:
- Numbers: 48 and 85
- Rounding:
- 48 rounds to 50 (nearest ten)
- 85 rounds to 90 (nearest ten)
- Sum: \( 50 + 90 = 140 \)
- Answer: 140

#### Problem 9:
- Numbers: 68 and 10
- Rounding:
- 68 rounds to 70 (nearest ten)
- 10 remains 10 (nearest ten)
- Sum: \( 70 + 10 = 80 \)
- Answer: 80

#### Problem 10:
- Numbers: 10 and 12
- Rounding:
- 10 remains 10 (nearest ten)
- 12 rounds to 10 (nearest ten)
- Difference: \( 10 - 10 = 0 \)
- Answer: 0

#### Problem 11:
- Numbers: 12 and 21
- Rounding:
- 12 rounds to 10 (nearest ten)
- 21 rounds to 20 (nearest ten)
- Difference: \( 10 - 20 = -10 \)
- Answer: -10

#### Problem 12:
- Numbers: 21 and 85
- Rounding:
- 21 rounds to 20 (nearest ten)
- 85 rounds to 90 (nearest ten)
- Sum: \( 20 + 90 = 110 \)
- Answer: 110

#### Problem 13:
- Numbers: 13 and 97
- Rounding:
- 13 rounds to 10 (nearest ten)
- 97 rounds to 100 (nearest ten)
- Sum: \( 10 + 100 = 110 \)
- Answer: 110

#### Problem 14:
- Numbers: 97 and 78
- Rounding:
- 97 rounds to 100 (nearest ten)
- 78 rounds to 80 (nearest ten)
- Difference: \( 100 - 80 = 20 \)
- Answer: 20

#### Problem 15:
- Numbers: 78 and 30
- Rounding:
- 78 rounds to 80 (nearest ten)
- 30 remains 30 (nearest ten)
- Sum: \( 80 + 30 = 110 \)
- Answer: 110

#### Problem 16:
- Numbers: 30 and 73
- Rounding:
- 30 remains 30 (nearest ten)
- 73 rounds to 70 (nearest ten)
- Difference: \( 30 - 70 = -40 \)
- Answer: -40

#### Problem 17:
- Numbers: 16 and 66
- Rounding:
- 16 rounds to 20 (nearest ten)
- 66 rounds to 70 (nearest ten)
- Sum: \( 20 + 70 = 90 \)
- Answer: 90

#### Problem 18:
- Numbers: 66 and 24
- Rounding:
- 66 rounds to 70 (nearest ten)
- 24 rounds to 20 (nearest ten)
- Difference: \( 70 - 20 = 50 \)
- Answer: 50

#### Problem 19:
- Numbers: 24 and 73
- Rounding:
- 24 rounds to 20 (nearest ten)
- 73 rounds to 70 (nearest ten)
- Sum: \( 20 + 70 = 90 \)
- Answer: 90

#### Problem 20:
- Numbers: 73 and 8
- Rounding:
- 73 rounds to 70 (nearest ten)
- 8 rounds to 10 (nearest ten)
- Difference: \( 70 - 10 = 60 \)
- Answer: 60

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Final Answers:

1. 190
2. 160
3. 10
4. 140
5. 140
6. 70
7. -40
8. 140
9. 80
10. 0
11. -10
12. 110
13. 110
14. 20
15. 110
16. -40
17. 90
18. 50
19. 90
20. 60

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Boxed Final Answer:
\[
\boxed{190, 160, 10, 140, 140, 70, -40, 140, 80, 0, -10, 110, 110, 20, 110, -40, 90, 50, 90, 60}
\]