Printable Grade 6 math worksheet featuring 20 addition problems where students must sum three numbers.

Let’s solve each addition problem step by step. I’ll group the numbers to make it easier — sometimes adding two first, then adding the third.

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1. 612 + 512 + 11

First: 612 + 512 = 1124
Then: 1124 + 11 = 1135

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2. 125 + 74 + 95

First: 125 + 74 = 199
Then: 199 + 95 = 294

*(Or: 125 + 95 = 220, then 220 + 74 = 294 — same result)*

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3. 916 + 51 + 437

First: 916 + 51 = 967
Then: 967 + 437 = 1404

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4. 189 + 191 + 96

First: 189 + 191 = 380
Then: 380 + 96 = 476

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5. 729 + 48 + 211

First: 729 + 48 = 777
Then: 777 + 211 = 988

*(Or: 729 + 211 = 940, then 940 + 48 = 988 — same)*

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6. 139 + 92 + 164

First: 139 + 92 = 231
Then: 231 + 164 = 395

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7. 82 + 617 + 429

First: 82 + 617 = 699
Then: 699 + 429 = 1128

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8. 362 + 14 + 66

First: 14 + 66 = 80 (easy!)
Then: 362 + 80 = 442

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9. 825 + 131 + 77

First: 825 + 131 = 956
Then: 956 + 77 = 1033

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10. 72 + 436 + 85

First: 72 + 436 = 508
Then: 508 + 85 = 593

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11. 906 + 59 + 412

First: 906 + 59 = 965
Then: 965 + 412 = 1377

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12. 25 + 63 + 457

First: 25 + 63 = 88
Then: 88 + 457 = 545

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13. 638 + 802 + 55

First: 638 + 802 = 1440
Then: 1440 + 55 = 1495

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14. 217 + 306 + 74

First: 217 + 306 = 523
Then: 523 + 74 = 597

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15. 435 + 128 + 65

First: 435 + 65 = 500 (nice round number!)
Then: 500 + 128 = 628

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16. 568 + 219 + 18

First: 568 + 219 = 787
Then: 787 + 18 = 805

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17. 76 + 142 + 93

First: 76 + 142 = 218
Then: 218 + 93 = 311

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18. 928 + 52 + 41

First: 928 + 52 = 980
Then: 980 + 41 = 1021

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19. 687 + 36 + 47

First: 687 + 36 = 723
Then: 723 + 47 = 770

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20. 819 + 25 + 36

First: 25 + 36 = 61
Then: 819 + 61 = 880

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Final Answer:
1. 1135
2. 294
3. 1404
4. 476
5. 988
6. 395
7. 1128
8. 442
9. 1033
10. 593
11. 1377
12. 545
13. 1495
14. 597
15. 628
16. 805
17. 311
18. 1021
19. 770
20. 880