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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 28 · 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. 1.572 − 213 =
  2. 2.887 − 716 =
  3. 3.521 + 469 =
  4. 4.785 + 487 =
  5. 5.403 + 185 =
  6. 6.775 + 357 =
  7. 7.727 + 153 =
  8. 8.244 + 193 =
  9. 9.677 + 469 =
  10. 10.493 + 174 =
  11. 11.945 − 569 =
  12. 12.896 − 226 =
  13. 13.554 − 378 =
  14. 14.266 + 312 =
  15. 15.779 − 583 =
  16. 16.884 − 219 =
  17. 17.783 − 183 =
  18. 18.166 + 329 =
  19. 19.459 + 306 =
  20. 20.462 + 196 =
  21. 21.157 + 223 =
  22. 22.947 − 482 =
  23. 23.544 − 421 =
  24. 24.139 + 502 =
  25. 25.227 + 508 =
  26. 26.591 − 165 =
  27. 27.687 + 292 =
  28. 28.963 − 351 =
  29. 29.839 − 287 =
  30. 30.678 + 309 =
  31. 31.682 + 552 =
  32. 32.170 + 587 =
  33. 33.245 + 438 =
  34. 34.747 + 591 =
  35. 35.334 + 405 =
  36. 36.925 − 305 =
  37. 37.760 − 487 =
  38. 38.338 + 202 =
  39. 39.748 + 228 =
  40. 40.340 + 228 =

Answer key

  1. 359
  2. 171
  3. 990
  4. 1272
  5. 588
  6. 1132
  7. 880
  8. 437
  9. 1146
  10. 667
  11. 376
  12. 670
  13. 176
  14. 578
  15. 196
  16. 665
  17. 600
  18. 495
  19. 765
  20. 658
  21. 380
  22. 465
  23. 123
  24. 641
  25. 735
  26. 426
  27. 979
  28. 612
  29. 552
  30. 987
  31. 1234
  32. 757
  33. 683
  34. 1338
  35. 739
  36. 620
  37. 273
  38. 540
  39. 976
  40. 568

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