Math worksheet for practicing addition of three-digit numbers with regrouping.

Let's solve each of these three-digit addition problems with regrouping step by step. We'll go through each problem carefully, showing how to add the numbers column by column (ones, tens, hundreds), carrying over when necessary.

---

Problem 1:

782 + 417

```
782
+ 417
-----
```

- Ones: 2 + 7 = 9 → write 9
- Tens: 8 + 1 = 9 → write 9
- Hundreds: 7 + 4 = 11 → write 11

Answer: 1199

---

Problem 2:

917 + 138

```
917
+ 138
-----
```

- Ones: 7 + 8 = 15 → write 5, carry 1
- Tens: 1 + 3 + 1 (carry) = 5 → write 5
- Hundreds: 9 + 1 = 10 → write 10

Answer: 1055

---

Problem 3:

197 + 517

```
197
+ 517
-----
```

- Ones: 7 + 7 = 14 → write 4, carry 1
- Tens: 9 + 1 + 1 = 11 → write 1, carry 1
- Hundreds: 1 + 5 + 1 = 7

Answer: 714

---

Problem 4:

448 + 667

```
448
+ 667
-----
```

- Ones: 8 + 7 = 15 → write 5, carry 1
- Tens: 4 + 6 + 1 = 11 → write 1, carry 1
- Hundreds: 4 + 6 + 1 = 11

Answer: 1115

---

Problem 5:

776 + 914

```
776
+ 914
-----
```

- Ones: 6 + 4 = 10 → write 0, carry 1
- Tens: 7 + 1 + 1 = 9 → write 9
- Hundreds: 7 + 9 = 16 → write 16

Answer: 1690

---

Problem 6:

641 + 558

```
641
+ 558
-----
```

- Ones: 1 + 8 = 9
- Tens: 4 + 5 = 9
- Hundreds: 6 + 5 = 11

Answer: 1199

---

Problem 7:

628 + 681

```
628
+ 681
-----
```

- Ones: 8 + 1 = 9
- Tens: 2 + 8 = 10 → write 0, carry 1
- Hundreds: 6 + 6 + 1 = 13

Answer: 1309

---

Problem 8:

659 + 148

```
659
+ 148
-----
```

- Ones: 9 + 8 = 17 → write 7, carry 1
- Tens: 5 + 4 + 1 = 10 → write 0, carry 1
- Hundreds: 6 + 1 + 1 = 8

Answer: 807

---

Problem 9:

109 + 788

```
109
+ 788
-----
```

- Ones: 9 + 8 = 17 → write 7, carry 1
- Tens: 0 + 8 + 1 = 9
- Hundreds: 1 + 7 = 8

Answer: 897

---

Problem 10:

458 + 775

```
458
+ 775
-----
```

- Ones: 8 + 5 = 13 → write 3, carry 1
- Tens: 5 + 7 + 1 = 13 → write 3, carry 1
- Hundreds: 4 + 7 + 1 = 12

Answer: 1233

---

Problem 11:

194 + 388

```
194
+ 388
-----
```

- Ones: 4 + 8 = 12 → write 2, carry 1
- Tens: 9 + 8 + 1 = 18 → write 8, carry 1
- Hundreds: 1 + 3 + 1 = 5

Answer: 582

---

Problem 12:

958 + 717

```
958
+ 717
-----
```

- Ones: 8 + 7 = 15 → write 5, carry 1
- Tens: 5 + 1 + 1 = 7
- Hundreds: 9 + 7 = 16

Answer: 1675

---

Problem 13:

229 + 518

```
229
+ 518
-----
```

- Ones: 9 + 8 = 17 → write 7, carry 1
- Tens: 2 + 1 + 1 = 4
- Hundreds: 2 + 5 = 7

Answer: 747

---

Problem 14:

579 + 555

```
579
+ 555
-----
```

- Ones: 9 + 5 = 14 → write 4, carry 1
- Tens: 7 + 5 + 1 = 13 → write 3, carry 1
- Hundreds: 5 + 5 + 1 = 11

Answer: 1134

---

Problem 15:

277 + 377

```
277
+ 377
-----
```

- Ones: 7 + 7 = 14 → write 4, carry 1
- Tens: 7 + 7 + 1 = 15 → write 5, carry 1
- Hundreds: 2 + 3 + 1 = 6

Answer: 654

---

Problem 16:

471 + 519

```
471
+ 519
-----
```

- Ones: 1 + 9 = 10 → write 0, carry 1
- Tens: 7 + 1 + 1 = 9
- Hundreds: 4 + 5 = 9

Answer: 990

---

Problem 17:

882 + 418

```
882
+ 418
-----
```

- Ones: 2 + 8 = 10 → write 0, carry 1
- Tens: 8 + 1 + 1 = 10 → write 0, carry 1
- Hundreds: 8 + 4 + 1 = 13

Answer: 1300

---

Problem 18:

881 + 617

```
881
+ 617
-----
```

- Ones: 1 + 7 = 8
- Tens: 8 + 1 = 9
- Hundreds: 8 + 6 = 14

Answer: 1498

---

Problem 19:

819 + 653

```
819
+ 653
-----
```

- Ones: 9 + 3 = 12 → write 2, carry 1
- Tens: 1 + 5 + 1 = 7
- Hundreds: 8 + 6 = 14

Answer: 1472

---

Problem 20:

991 + 433

```
991
+ 433
-----
```

- Ones: 1 + 3 = 4
- Tens: 9 + 3 = 12 → write 2, carry 1
- Hundreds: 9 + 4 + 1 = 14

Answer: 1424

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✔ Final Answers:

| Problem | Answer |
|--------|--------|
| 1 | 1199 |
| 2 | 1055 |
| 3 | 714 |
| 4 | 1115 |
| 5 | 1690 |
| 6 | 1199 |
| 7 | 1309 |
| 8 | 807 |
| 9 | 897 |
| 10 | 1233 |
| 11 | 582 |
| 12 | 1675 |
| 13 | 747 |
| 14 | 1134 |
| 15 | 654 |
| 16 | 990 |
| 17 | 1300 |
| 18 | 1498 |
| 19 | 1472 |
| 20 | 1424 |

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✔ All problems solved with proper regrouping! Let me know if you'd like this as a printable worksheet or with step-by-step visuals.