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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 652 · 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. 1.669 + 539 =
  2. 2.747 − 181 =
  3. 3.476 − 159 =
  4. 4.551 − 327 =
  5. 5.677 − 322 =
  6. 6.959 − 676 =
  7. 7.630 + 582 =
  8. 8.364 + 641 =
  9. 9.441 − 161 =
  10. 10.546 − 207 =
  11. 11.592 − 231 =
  12. 12.636 − 431 =
  13. 13.466 + 281 =
  14. 14.461 − 316 =
  15. 15.244 + 574 =
  16. 16.180 + 577 =
  17. 17.765 + 166 =
  18. 18.793 − 562 =
  19. 19.159 + 401 =
  20. 20.363 + 431 =
  21. 21.715 − 607 =
  22. 22.778 − 161 =
  23. 23.829 − 231 =
  24. 24.243 + 198 =
  25. 25.457 − 237 =
  26. 26.273 + 604 =
  27. 27.593 + 636 =
  28. 28.290 + 205 =
  29. 29.454 − 121 =
  30. 30.728 − 127 =
  31. 31.701 − 261 =
  32. 32.685 + 393 =
  33. 33.498 + 496 =
  34. 34.598 − 173 =
  35. 35.666 − 494 =
  36. 36.703 − 291 =
  37. 37.597 + 248 =
  38. 38.532 − 371 =
  39. 39.539 + 263 =
  40. 40.196 + 258 =

Answer key

  1. 1208
  2. 566
  3. 317
  4. 224
  5. 355
  6. 283
  7. 1212
  8. 1005
  9. 280
  10. 339
  11. 361
  12. 205
  13. 747
  14. 145
  15. 818
  16. 757
  17. 931
  18. 231
  19. 560
  20. 794
  21. 108
  22. 617
  23. 598
  24. 441
  25. 220
  26. 877
  27. 1229
  28. 495
  29. 333
  30. 601
  31. 440
  32. 1078
  33. 994
  34. 425
  35. 172
  36. 412
  37. 845
  38. 161
  39. 802
  40. 454

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