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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 498 · 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. 1.960 − 551 =
  2. 2.699 − 406 =
  3. 3.432 + 431 =
  4. 4.581 + 263 =
  5. 5.438 + 253 =
  6. 6.705 + 488 =
  7. 7.477 − 214 =
  8. 8.701 − 285 =
  9. 9.773 + 571 =
  10. 10.653 − 131 =
  11. 11.522 + 316 =
  12. 12.675 + 241 =
  13. 13.790 − 264 =
  14. 14.291 + 341 =
  15. 15.725 + 607 =
  16. 16.293 + 231 =
  17. 17.474 − 329 =
  18. 18.749 − 348 =
  19. 19.666 − 205 =
  20. 20.630 + 117 =
  21. 21.427 − 162 =
  22. 22.264 + 601 =
  23. 23.977 − 334 =
  24. 24.689 + 572 =
  25. 25.944 − 495 =
  26. 26.601 + 337 =
  27. 27.622 + 439 =
  28. 28.649 − 265 =
  29. 29.233 + 331 =
  30. 30.401 + 558 =
  31. 31.239 + 385 =
  32. 32.948 − 781 =
  33. 33.236 + 496 =
  34. 34.619 + 589 =
  35. 35.811 − 243 =
  36. 36.849 − 441 =
  37. 37.754 + 346 =
  38. 38.436 − 226 =
  39. 39.897 − 149 =
  40. 40.654 + 394 =

Answer key

  1. 409
  2. 293
  3. 863
  4. 844
  5. 691
  6. 1193
  7. 263
  8. 416
  9. 1344
  10. 522
  11. 838
  12. 916
  13. 526
  14. 632
  15. 1332
  16. 524
  17. 145
  18. 401
  19. 461
  20. 747
  21. 265
  22. 865
  23. 643
  24. 1261
  25. 449
  26. 938
  27. 1061
  28. 384
  29. 564
  30. 959
  31. 624
  32. 167
  33. 732
  34. 1208
  35. 568
  36. 408
  37. 1100
  38. 210
  39. 748
  40. 1048

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