Math worksheet for estimating addition by rounding numbers to the nearest hundred and thousand.

Let's solve the worksheet step by step. The task is to estimate the addition by rounding each number to either the nearest hundred or the nearest thousand, depending on the section.

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🔹 Section 1: Estimate by rounding to the nearest hundred

We'll round each number to the nearest 100, then add.

#### Example:
To round to the nearest hundred:
- Look at the tens digit.
- If it’s 5 or more, round up.
- If less than 5, round down.

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1. 324 + 454
- 324 → 300 (tens digit is 2 < 5)
- 454 → 500 (tens digit is 5 → round up)
- Estimated sum: 300 + 500 = 800

2. 965 + 457
- 965 → 1000 (tens digit is 6 ≥ 5 → round up)
- 457 → 500
- Estimated sum: 1000 + 500 = 1500

3. 325 + 247
- 325 → 300 (tens digit is 2 < 5)
- 247 → 200 (tens digit is 4 < 5)
- Estimated sum: 300 + 200 = 500

4. 365 + 124
- 365 → 400 (tens digit is 6 ≥ 5)
- 124 → 100 (tens digit is 2 < 5)
- Estimated sum: 400 + 100 = 500

5. 365 + 247
- 365 → 400
- 247 → 200
- Estimated sum: 400 + 200 = 600

6. 987 + 214
- 987 → 1000 (tens digit is 8 ≥ 5)
- 214 → 200 (tens digit is 1 < 5)
- Estimated sum: 1000 + 200 = 1200

7. 632 + 247
- 632 → 600 (tens digit is 3 < 5)
- 247 → 200
- Estimated sum: 600 + 200 = 800

8. 987 + 247
- 987 → 1000
- 247 → 200
- Estimated sum: 1000 + 200 = 1200

9. 365 + 247
- Same as #5 → 400 + 200 = 600

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✔ Section 1 Answers:

| Problem | Rounded | Estimated Sum |
|--------|--------|----------------|
| 324 + 454 → | 300 + 500 = 800 |
| 965 + 457 → | 1000 + 500 = 1500 |
| 325 + 247 → | 300 + 200 = 500 |
| 365 + 124 → | 400 + 100 = 500 |
| 365 + 247 → | 400 + 200 = 600 |
| 987 + 214 → | 1000 + 200 = 1200 |
| 632 + 247 → | 600 + 200 = 800 |
| 987 + 247 → | 1000 + 200 = 1200 |
| 365 + 247 → | 400 + 200 = 600 |

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🔹 Section 2: Estimate by rounding to the nearest thousand

Now we round each number to the nearest 1000.

Rules:
- Look at the hundreds digit.
- If it’s 500 or more, round up.
- If less than 500, round down.

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1. 2547 + 3214
- 2547 → 3000 (hundreds digit is 5 → round up)
- 3214 → 3000 (hundreds digit is 2 < 5)
- Estimated sum: 3000 + 3000 = 6000

2. 3214 + 1247
- 3214 → 3000
- 1247 → 1000 (hundreds digit is 2 < 5)
- Estimated sum: 3000 + 1000 = 4000

3. 3698 + 2471
- 3698 → 4000 (hundreds digit is 6 ≥ 5)
- 2471 → 2000 (hundreds digit is 4 < 5)
- Estimated sum: 4000 + 2000 = 6000

4. 3254 + 2478
- 3254 → 3000 (hundreds digit is 2 < 5)
- 2478 → 2000 (hundreds digit is 4 < 5)
- Estimated sum: 3000 + 2000 = 5000

5. 9874 + 3254
- 9874 → 10000 (hundreds digit is 8 ≥ 5 → round up)
- 3254 → 3000
- Estimated sum: 10000 + 3000 = 13000

6. 3247 + 7841
- 3247 → 3000
- 7841 → 8000 (hundreds digit is 8 ≥ 5)
- Estimated sum: 3000 + 8000 = 11000

7. 9654 + 3254
- 9654 → 10000 (hundreds digit is 6 ≥ 5)
- 3254 → 3000
- Estimated sum: 10000 + 3000 = 13000

8. 4875 + 4214
- 4875 → 5000 (hundreds digit is 8 ≥ 5)
- 4214 → 4000 (hundreds digit is 2 < 5)
- Estimated sum: 5000 + 4000 = 9000

9. 2321 + 1245
- 2321 → 2000 (hundreds digit is 3 < 5)
- 1245 → 1000 (hundreds digit is 2 < 5)
- Estimated sum: 2000 + 1000 = 3000

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✔ Section 2 Answers:

| Problem | Rounded | Estimated Sum |
|--------|--------|----------------|
| 2547 + 3214 → | 3000 + 3000 = 6000 |
| 3214 + 1247 → | 3000 + 1000 = 4000 |
| 3698 + 2471 → | 4000 + 2000 = 6000 |
| 3254 + 2478 → | 3000 + 2000 = 5000 |
| 9874 + 3254 → | 10000 + 3000 = 13000 |
| 3247 + 7841 → | 3000 + 8000 = 11000 |
| 9654 + 3254 → | 10000 + 3000 = 13000 |
| 4875 + 4214 → | 5000 + 4000 = 9000 |
| 2321 + 1245 → | 2000 + 1000 = 3000 |

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📌 Final Answer Summary:

#### Rounding to Nearest Hundred:
```
324 → 300 + 454 → 500 = 800
965 → 1000 + 457 → 500 = 1500
325 → 300 + 247 → 200 = 500
365 → 400 + 124 → 100 = 500
365 → 400 + 247 → 200 = 600
987 → 1000 + 214 → 200 = 1200
632 → 600 + 247 → 200 = 800
987 → 1000 + 247 → 200 = 1200
365 → 400 + 247 → 200 = 600
```

#### Rounding to Nearest Thousand:
```
2547 → 3000 + 3214 → 3000 = 6000
3214 → 3000 + 1247 → 1000 = 4000
3698 → 4000 + 2471 → 2000 = 6000
3254 → 3000 + 2478 → 2000 = 5000
9874 → 10000 + 3254 → 3000 = 13000
3247 → 3000 + 7841 → 8000 = 11000
9654 → 10000 + 3254 → 3000 = 13000
4875 → 5000 + 4214 → 4000 = 9000
2321 → 2000 + 1245 → 1000 = 3000
```

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✔ Explanation:
Estimation helps us quickly find approximate sums without exact calculations. Rounding makes numbers easier to work with, especially in mental math. Always remember:
- For nearest hundred: look at the tens place.
- For nearest thousand: look at the hundreds place.

This method is useful for checking if your exact answer is reasonable.