3 Digit Addition Worksheets - Free Printable

Let’s solve each problem step by step. We’ll add the numbers column by column, starting from the right (ones place), then tens, then hundreds. If a column adds up to 10 or more, we carry over to the next column.

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Problem 1: 165 + 54 + 223

Ones: 5 + 4 + 3 = 12 → write 2, carry 1
Tens: 6 + 5 + 2 + 1 (carry) = 14 → write 4, carry 1
Hundreds: 1 + 0 + 2 + 1 (carry) = 4
→ 442

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Problem 2: 406 + 153 + 325

Ones: 6 + 3 + 5 = 14 → write 4, carry 1
Tens: 0 + 5 + 2 + 1 = 8
Hundreds: 4 + 1 + 3 = 8
→ 884

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Problem 3: 276 + 134 + 65

Ones: 6 + 4 + 5 = 15 → write 5, carry 1
Tens: 7 + 3 + 6 + 1 = 17 → write 7, carry 1
Hundreds: 2 + 1 + 0 + 1 = 4
→ 475

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Problem 4: 424 + 336 + 151

Ones: 4 + 6 + 1 = 11 → write 1, carry 1
Tens: 2 + 3 + 5 + 1 = 11 → write 1, carry 1
Hundreds: 4 + 3 + 1 + 1 = 9
→ 911

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Problem 5: 243 + 228 + 76

Ones: 3 + 8 + 6 = 17 → write 7, carry 1
Tens: 4 + 2 + 7 + 1 = 14 → write 4, carry 1
Hundreds: 2 + 2 + 0 + 1 = 5
→ 547

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Problem 6: 382 + 156 + 227

Ones: 2 + 6 + 7 = 15 → write 5, carry 1
Tens: 8 + 5 + 2 + 1 = 16 → write 6, carry 1
Hundreds: 3 + 1 + 2 + 1 = 7
→ 765

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Problem 7: 513 + 243 + 165

Ones: 3 + 3 + 5 = 11 → write 1, carry 1
Tens: 1 + 4 + 6 + 1 = 12 → write 2, carry 1
Hundreds: 5 + 2 + 1 + 1 = 9
→ 921

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Problem 8: 343 + 256 + 308

Ones: 3 + 6 + 8 = 17 → write 7, carry 1
Tens: 4 + 5 + 0 + 1 = 10 → write 0, carry 1
Hundreds: 3 + 2 + 3 + 1 = 9
→ 907

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Problem 9: 527 + 65 + 336

Ones: 7 + 5 + 6 = 18 → write 8, carry 1
Tens: 2 + 6 + 3 + 1 = 12 → write 2, carry 1
Hundreds: 5 + 0 + 3 + 1 = 9
→ 928

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Problem 10: 342 + 128 + 86

Ones: 2 + 8 + 6 = 16 → write 6, carry 1
Tens: 4 + 2 + 8 + 1 = 15 → write 5, carry 1
Hundreds: 3 + 1 + 0 + 1 = 5
→ 556

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Problem 11: 287 + 156 + 224

Ones: 7 + 6 + 4 = 17 → write 7, carry 1
Tens: 8 + 5 + 2 + 1 = 16 → write 6, carry 1
Hundreds: 2 + 1 + 2 + 1 = 6
→ 667

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Problem 12: 329 + 308 + 175

Ones: 9 + 8 + 5 = 22 → write 2, carry 2
Tens: 2 + 0 + 7 + 2 = 11 → write 1, carry 1
Hundreds: 3 + 3 + 1 + 1 = 8
→ 812

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Problem 13: 336 + 151 + 270

Ones: 6 + 1 + 0 = 7
Tens: 3 + 5 + 7 = 15 → write 5, carry 1
Hundreds: 3 + 1 + 2 + 1 = 7
→ 757

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Problem 14: 563 + 37 + 239

Ones: 3 + 7 + 9 = 19 → write 9, carry 1
Tens: 6 + 3 + 3 + 1 = 13 → write 3, carry 1
Hundreds: 5 + 0 + 2 + 1 = 8
→ 839

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Problem 15: 228 + 360 + 96

Ones: 8 + 0 + 6 = 14 → write 4, carry 1
Tens: 2 + 6 + 9 + 1 = 18 → write 8, carry 1
Hundreds: 2 + 3 + 0 + 1 = 6
→ 684

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Problem 16: 549 + 63 + 37

Ones: 9 + 3 + 7 = 19 → write 9, carry 1
Tens: 4 + 6 + 3 + 1 = 14 → write 4, carry 1
Hundreds: 5 + 0 + 0 + 1 = 6
→ 649

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Problem 17: 420 + 217 + 348

Ones: 0 + 7 + 8 = 15 → write 5, carry 1
Tens: 2 + 1 + 4 + 1 = 8
Hundreds: 4 + 2 + 3 = 9
→ 985

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Problem 18: 155 + 128 + 137

Ones: 5 + 8 + 7 = 20 → write 0, carry 2
Tens: 5 + 2 + 3 + 2 = 12 → write 2, carry 1
Hundreds: 1 + 1 + 1 + 1 = 4
→ 420

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Problem 19: 497 + 65 + 284

Ones: 7 + 5 + 4 = 16 → write 6, carry 1
Tens: 9 + 6 + 8 + 1 = 24 → write 4, carry 2
Hundreds: 4 + 0 + 2 + 2 = 8
→ 846

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Problem 20: 337 + 366 + 245

Ones: 7 + 6 + 5 = 18 → write 8, carry 1
Tens: 3 + 6 + 4 + 1 = 14 → write 4, carry 1
Hundreds: 3 + 3 + 2 + 1 = 9
→ 948

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Final Answer:
1) 442
2) 884
3) 475
4) 911
5) 547
6) 765
7) 921
8) 907
9) 928
10) 556
11) 667
12) 812
13) 757
14) 839
15) 684
16) 649
17) 985
18) 420
19) 846
20) 948