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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 422 · 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. 1.532 − 363 =
  2. 2.926 − 391 =
  3. 3.501 − 354 =
  4. 4.535 + 571 =
  5. 5.383 + 465 =
  6. 6.348 + 616 =
  7. 7.378 + 303 =
  8. 8.173 + 677 =
  9. 9.622 + 159 =
  10. 10.187 + 687 =
  11. 11.170 + 636 =
  12. 12.570 + 357 =
  13. 13.523 + 435 =
  14. 14.427 − 137 =
  15. 15.288 + 125 =
  16. 16.576 − 161 =
  17. 17.751 + 403 =
  18. 18.602 − 235 =
  19. 19.584 + 401 =
  20. 20.931 − 442 =
  21. 21.738 − 231 =
  22. 22.909 − 137 =
  23. 23.631 + 444 =
  24. 24.413 + 207 =
  25. 25.764 − 253 =
  26. 26.148 + 148 =
  27. 27.801 − 556 =
  28. 28.726 + 204 =
  29. 29.468 + 436 =
  30. 30.976 − 601 =
  31. 31.462 − 164 =
  32. 32.970 − 411 =
  33. 33.563 − 324 =
  34. 34.577 − 348 =
  35. 35.727 − 409 =
  36. 36.201 + 456 =
  37. 37.483 − 212 =
  38. 38.270 + 641 =
  39. 39.661 + 228 =
  40. 40.937 − 326 =

Answer key

  1. 169
  2. 535
  3. 147
  4. 1106
  5. 848
  6. 964
  7. 681
  8. 850
  9. 781
  10. 874
  11. 806
  12. 927
  13. 958
  14. 290
  15. 413
  16. 415
  17. 1154
  18. 367
  19. 985
  20. 489
  21. 507
  22. 772
  23. 1075
  24. 620
  25. 511
  26. 296
  27. 245
  28. 930
  29. 904
  30. 375
  31. 298
  32. 559
  33. 239
  34. 229
  35. 318
  36. 657
  37. 271
  38. 911
  39. 889
  40. 611

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