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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 592 · 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. 1.222 + 631 =
  2. 2.847 − 372 =
  3. 3.697 − 566 =
  4. 4.665 − 396 =
  5. 5.693 + 645 =
  6. 6.399 + 341 =
  7. 7.683 + 421 =
  8. 8.635 − 357 =
  9. 9.719 + 272 =
  10. 10.655 − 357 =
  11. 11.560 − 141 =
  12. 12.329 + 442 =
  13. 13.238 + 632 =
  14. 14.618 − 276 =
  15. 15.577 + 188 =
  16. 16.427 + 353 =
  17. 17.323 + 619 =
  18. 18.251 + 351 =
  19. 19.699 − 535 =
  20. 20.945 − 253 =
  21. 21.602 + 245 =
  22. 22.612 + 258 =
  23. 23.622 + 261 =
  24. 24.833 − 463 =
  25. 25.609 + 434 =
  26. 26.675 + 585 =
  27. 27.515 + 499 =
  28. 28.135 + 148 =
  29. 29.938 − 118 =
  30. 30.250 + 214 =
  31. 31.585 + 203 =
  32. 32.704 − 475 =
  33. 33.530 + 583 =
  34. 34.528 + 382 =
  35. 35.185 + 195 =
  36. 36.192 + 538 =
  37. 37.498 − 141 =
  38. 38.378 + 133 =
  39. 39.630 − 405 =
  40. 40.412 + 194 =

Answer key

  1. 853
  2. 475
  3. 131
  4. 269
  5. 1338
  6. 740
  7. 1104
  8. 278
  9. 991
  10. 298
  11. 419
  12. 771
  13. 870
  14. 342
  15. 765
  16. 780
  17. 942
  18. 602
  19. 164
  20. 692
  21. 847
  22. 870
  23. 883
  24. 370
  25. 1043
  26. 1260
  27. 1014
  28. 283
  29. 820
  30. 464
  31. 788
  32. 229
  33. 1113
  34. 910
  35. 380
  36. 730
  37. 357
  38. 511
  39. 225
  40. 606

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