Adding and Estimation Worksheet - Free Printable

Sure! Let’s solve each problem by estimating the sum first (by rounding to the nearest ten or hundred, whichever makes sense for quick mental math), and then calculating the actual sum.

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📌 General Strategy:

- Estimate: Round each number to the nearest 10 or 100, then add.
- Actual: Add the original numbers carefully.

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## ✔ Problem 1: 145 + 325

- Estimate:
145 → 150
325 → 330
150 + 330 = 480

- Actual:
145 + 325 = 470

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## ✔ Problem 2: 572 + 227

- Estimate:
572 → 570
227 → 230
570 + 230 = 800

- Actual:
572 + 227 = 799

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## ✔ Problem 3: 166 + 622

- Estimate:
166 → 170
622 → 620
170 + 620 = 790

- Actual:
166 + 622 = 788

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## ✔ Problem 4: 608 + 321

- Estimate:
608 → 610
321 → 320
610 + 320 = 930

- Actual:
608 + 321 = 929

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## ✔ Problem 5: 455 + 213

- Estimate:
455 → 460
213 → 210
460 + 210 = 670

- Actual:
455 + 213 = 668

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## ✔ Problem 6: 326 + 321

- Estimate:
326 → 330
321 → 320
330 + 320 = 650

- Actual:
326 + 321 = 647

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## ✔ Problem 7: 309 + 381

- Estimate:
309 → 310
381 → 380
310 + 380 = 690

- Actual:
309 + 381 = 690 ← *Perfect estimate!*

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## ✔ Problem 8: 486 + 201

- Estimate:
486 → 490
201 → 200
490 + 200 = 690

- Actual:
486 + 201 = 687

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## 📝 Final Answers:

| Problem | Estimate | Actual |
|---------|----------|--------|
| 1 | 480 | 470 |
| 2 | 800 | 799 |
| 3 | 790 | 788 |
| 4 | 930 | 929 |
| 5 | 670 | 668 |
| 6 | 650 | 647 |
| 7 | 690 | 690 |
| 8 | 690 | 687 |

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✔ Tip: Estimation helps you quickly check if your actual answer is reasonable. If your actual answer is far from your estimate, double-check your addition!

Let me know if you’d like this formatted as a printable worksheet or explained differently!