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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 931 · 40 questions
TalentJR

How to do it in your head (Hundreds first): Keep the first number as it is and split the second into hundreds, tens and ones. Add (or take away) the hundreds first, then the tens. Finish with the ones — bridge through a ten if you need to.

NameDateTime takenScore ___ / 40
  1. 1.969 − 286 =
  2. 2.925 − 654 =
  3. 3.933 − 366 =
  4. 4.736 − 151 =
  5. 5.722 + 195 =
  6. 6.364 + 361 =
  7. 7.885 − 224 =
  8. 8.537 − 132 =
  9. 9.249 + 479 =
  10. 10.926 − 354 =
  11. 11.567 + 579 =
  12. 12.437 − 211 =
  13. 13.911 − 345 =
  14. 14.654 − 431 =
  15. 15.623 − 273 =
  16. 16.706 + 307 =
  17. 17.575 + 119 =
  18. 18.506 + 246 =
  19. 19.850 − 497 =
  20. 20.657 − 475 =
  21. 21.396 + 571 =
  22. 22.550 − 391 =
  23. 23.491 − 321 =
  24. 24.743 + 452 =
  25. 25.182 + 352 =
  26. 26.502 + 257 =
  27. 27.726 + 365 =
  28. 28.196 + 236 =
  29. 29.272 + 393 =
  30. 30.558 + 323 =
  31. 31.196 + 529 =
  32. 32.620 − 266 =
  33. 33.899 − 563 =
  34. 34.606 − 316 =
  35. 35.178 + 195 =
  36. 36.269 + 355 =
  37. 37.302 + 635 =
  38. 38.722 + 332 =
  39. 39.487 − 131 =
  40. 40.640 − 304 =

Answer key

  1. 683
  2. 271
  3. 567
  4. 585
  5. 917
  6. 725
  7. 661
  8. 405
  9. 728
  10. 572
  11. 1146
  12. 226
  13. 566
  14. 223
  15. 350
  16. 1013
  17. 694
  18. 752
  19. 353
  20. 182
  21. 967
  22. 159
  23. 170
  24. 1195
  25. 534
  26. 759
  27. 1091
  28. 432
  29. 665
  30. 881
  31. 725
  32. 354
  33. 336
  34. 290
  35. 373
  36. 624
  37. 937
  38. 1054
  39. 356
  40. 336

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