3-Digit Mixed Addition and Subtraction Worksheet with Birthday Theme

Let's solve each of the 3-digit mixed addition and subtraction problems with regrouping from the worksheet titled *"Birthday Party Problems."* I'll go step by step, showing how to solve each problem and explain the process.

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🔢 Problem Set:

We’ll solve all 20 problems. Let’s do them one at a time.

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#### 1. 523 + 786
```
523
+ 786
-----
```
- Ones: 3 + 6 = 9
- Tens: 2 + 8 = 10 → write 0, carry 1
- Hundreds: 5 + 7 + 1 (carry) = 13
✔ Answer: 1309

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#### 2. 732 - 382
```
732
- 382
-----
```
- Ones: 2 - 2 = 0
- Tens: 3 - 8 → can't do, borrow from hundreds
- 13 - 8 = 5 (after borrowing, tens become 13)
- Hundreds: 6 (after borrowing) - 3 = 3
✔ Answer: 350

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#### 3. 441 + 569
```
441
+ 569
-----
```
- Ones: 1 + 9 = 10 → write 0, carry 1
- Tens: 4 + 6 + 1 = 11 → write 1, carry 1
- Hundreds: 4 + 5 + 1 = 10
✔ Answer: 1010

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#### 4. 869 - 778
```
869
- 778
-----
```
- Ones: 9 - 8 = 1
- Tens: 6 - 7 → can't do, borrow
- 16 - 7 = 9 (tens become 16 after borrowing)
- Hundreds: 7 (after borrowing) - 7 = 0
✔ Answer: 91

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#### 5. 339 + 528
```
339
+ 528
-----
```
- Ones: 9 + 8 = 17 → write 7, carry 1
- Tens: 3 + 2 + 1 = 6
- Hundreds: 3 + 5 = 8
✔ Answer: 867

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#### 6. 889 - 699
```
889
- 699
-----
```
- Ones: 9 - 9 = 0
- Tens: 8 - 9 → borrow
- 18 - 9 = 9 (tens become 18)
- Hundreds: 7 (after borrowing) - 6 = 1
✔ Answer: 190

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#### 7. 412 + 818
```
412
+ 818
-----
```
- Ones: 2 + 8 = 10 → write 0, carry 1
- Tens: 1 + 1 + 1 = 3
- Hundreds: 4 + 8 = 12
✔ Answer: 1230

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#### 8. 322 - 174
```
322
- 174
-----
```
- Ones: 2 - 4 → borrow
- 12 - 4 = 8
- Tens: 1 (after borrowing) - 7 → can't do, borrow again
- 11 - 7 = 4
- Hundreds: 2 (after borrowing) - 1 = 1
✔ Answer: 148

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#### 9. 274 + 299
```
274
+ 299
-----
```
- Ones: 4 + 9 = 13 → write 3, carry 1
- Tens: 7 + 9 + 1 = 17 → write 7, carry 1
- Hundreds: 2 + 2 + 1 = 5
✔ Answer: 573

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#### 10. 323 - 168
```
323
- 168
-----
```
- Ones: 3 - 8 → borrow
- 13 - 8 = 5
- Tens: 1 (after borrowing) - 6 → borrow again
- 11 - 6 = 5
- Hundreds: 2 (after borrowing) - 1 = 1
✔ Answer: 155

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#### 11. 226 + 286
```
226
+ 286
-----
```
- Ones: 6 + 6 = 12 → write 2, carry 1
- Tens: 2 + 8 + 1 = 11 → write 1, carry 1
- Hundreds: 2 + 2 + 1 = 5
✔ Answer: 512

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#### 12. 588 - 293
```
588
- 293
-----
```
- Ones: 8 - 3 = 5
- Tens: 8 - 9 → borrow
- 18 - 9 = 9
- Hundreds: 4 (after borrowing) - 2 = 2
✔ Answer: 295

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#### 13. 726 + 189
```
726
+ 189
-----
```
- Ones: 6 + 9 = 15 → write 5, carry 1
- Tens: 2 + 8 + 1 = 11 → write 1, carry 1
- Hundreds: 7 + 1 + 1 = 9
✔ Answer: 915

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#### 14. 659 - 368
```
659
- 368
-----
```
- Ones: 9 - 8 = 1
- Tens: 5 - 6 → borrow
- 15 - 6 = 9
- Hundreds: 5 (after borrowing) - 3 = 2
✔ Answer: 291

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#### 15. 323 + 592
```
323
+ 592
-----
```
- Ones: 3 + 2 = 5
- Tens: 2 + 9 = 11 → write 1, carry 1
- Hundreds: 3 + 5 + 1 = 9
✔ Answer: 915

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#### 16. 693 - 287
```
693
- 287
-----
```
- Ones: 3 - 7 → borrow
- 13 - 7 = 6
- Tens: 8 (after borrowing) - 8 = 0
- Hundreds: 6 - 2 = 4
✔ Answer: 406

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#### 17. 342 + 185
```
342
+ 185
-----
```
- Ones: 2 + 5 = 7
- Tens: 4 + 8 = 12 → write 2, carry 1
- Hundreds: 3 + 1 + 1 = 5
✔ Answer: 527

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#### 18. 404 - 272
```
404
- 272
-----
```
- Ones: 4 - 2 = 2
- Tens: 0 - 7 → borrow
- 10 - 7 = 3
- Hundreds: 3 (after borrowing) - 2 = 1
✔ Answer: 132

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#### 19. 748 - 359
```
748
- 359
-----
```
- Ones: 8 - 9 → borrow
- 18 - 9 = 9
- Tens: 3 (after borrowing) - 5 → borrow again
- 13 - 5 = 8
- Hundreds: 6 (after borrowing) - 3 = 3
✔ Answer: 389

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#### 20. 532 + 448
```
532
+ 448
-----
```
- Ones: 2 + 8 = 10 → write 0, carry 1
- Tens: 3 + 4 + 1 = 8
- Hundreds: 5 + 4 = 9
✔ Answer: 980

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#### 21. 545 - 267
```
545
- 267
-----
```
- Ones: 5 - 7 → borrow
- 15 - 7 = 8
- Tens: 3 (after borrowing) - 6 → borrow again
- 13 - 6 = 7
- Hundreds: 4 (after borrowing) - 2 = 2
✔ Answer: 278

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#### 22. 225 - 166
```
225
- 166
-----
```
- Ones: 5 - 6 → borrow
- 15 - 6 = 9
- Tens: 1 (after borrowing) - 6 → borrow again
- 11 - 6 = 5
- Hundreds: 1 (after borrowing) - 1 = 0
✔ Answer: 59

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#### 23. 878 + 124
```
878
+ 124
-----
```
- Ones: 8 + 4 = 12 → write 2, carry 1
- Tens: 7 + 2 + 1 = 10 → write 0, carry 1
- Hundreds: 8 + 1 + 1 = 10
✔ Answer: 1002

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#### 24. 555 - 469
```
555
- 469
-----
```
- Ones: 5 - 9 → borrow
- 15 - 9 = 6
- Tens: 4 (after borrowing) - 6 → borrow again
- 14 - 6 = 8
- Hundreds: 4 (after borrowing) - 4 = 0
✔ Answer: 86

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✔ Final Answers:

| Problem | Answer |
|--------|--------|
| 1. 523 + 786 | 1309 |
| 2. 732 - 382 | 350 |
| 3. 441 + 569 | 1010 |
| 4. 869 - 778 | 91 |
| 5. 339 + 528 | 867 |
| 6. 889 - 699 | 190 |
| 7. 412 + 818 | 1230 |
| 8. 322 - 174 | 148 |
| 9. 274 + 299 | 573 |
|10. 323 - 168 | 155 |
|11. 226 + 286 | 512 |
|12. 588 - 293 | 295 |
|13. 726 + 189 | 915 |
|14. 659 - 368 | 291 |
|15. 323 + 592 | 915 |
|16. 693 - 287 | 406 |
|17. 342 + 185 | 527 |
|18. 404 - 272 | 132 |
|19. 748 - 359 | 389 |
|20. 532 + 448 | 980 |
|21. 545 - 267 | 278 |
|22. 225 - 166 | 59 |
|23. 878 + 124 | 1002 |
|24. 555 - 469 | 86 |

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🎉 Summary:

This worksheet practices 3-digit addition and subtraction with regrouping, which is key for building number sense and arithmetic fluency. Each problem requires careful attention to place value and borrowing/carrying.

If you'd like this in printable format or need help explaining any specific problem, let me know! 🍕🎈