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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 593 · 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. 1.491 − 382 =
  2. 2.641 + 354 =
  3. 3.219 + 346 =
  4. 4.248 + 152 =
  5. 5.873 − 292 =
  6. 6.510 + 267 =
  7. 7.528 − 358 =
  8. 8.739 + 586 =
  9. 9.602 − 237 =
  10. 10.642 − 205 =
  11. 11.543 − 229 =
  12. 12.955 − 359 =
  13. 13.601 + 563 =
  14. 14.416 − 175 =
  15. 15.410 + 541 =
  16. 16.576 − 418 =
  17. 17.326 + 591 =
  18. 18.564 + 686 =
  19. 19.771 − 572 =
  20. 20.626 − 146 =
  21. 21.459 − 139 =
  22. 22.603 + 125 =
  23. 23.469 + 262 =
  24. 24.478 − 125 =
  25. 25.221 + 522 =
  26. 26.287 + 211 =
  27. 27.886 − 258 =
  28. 28.405 + 653 =
  29. 29.402 + 358 =
  30. 30.288 + 333 =
  31. 31.381 + 231 =
  32. 32.860 − 422 =
  33. 33.681 − 185 =
  34. 34.228 + 182 =
  35. 35.220 + 236 =
  36. 36.144 + 456 =
  37. 37.845 − 697 =
  38. 38.302 + 127 =
  39. 39.182 + 369 =
  40. 40.806 − 601 =

Answer key

  1. 109
  2. 995
  3. 565
  4. 400
  5. 581
  6. 777
  7. 170
  8. 1325
  9. 365
  10. 437
  11. 314
  12. 596
  13. 1164
  14. 241
  15. 951
  16. 158
  17. 917
  18. 1250
  19. 199
  20. 480
  21. 320
  22. 728
  23. 731
  24. 353
  25. 743
  26. 498
  27. 628
  28. 1058
  29. 760
  30. 621
  31. 612
  32. 438
  33. 496
  34. 410
  35. 456
  36. 600
  37. 148
  38. 429
  39. 551
  40. 205

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