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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 963 · 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. 1.758 − 237 =
  2. 2.568 − 251 =
  3. 3.451 + 245 =
  4. 4.635 + 335 =
  5. 5.318 + 131 =
  6. 6.287 + 434 =
  7. 7.477 + 348 =
  8. 8.257 + 261 =
  9. 9.764 − 131 =
  10. 10.939 − 564 =
  11. 11.188 + 201 =
  12. 12.772 − 274 =
  13. 13.660 + 211 =
  14. 14.796 − 251 =
  15. 15.783 − 597 =
  16. 16.903 − 247 =
  17. 17.575 + 609 =
  18. 18.123 + 292 =
  19. 19.141 + 566 =
  20. 20.726 − 581 =
  21. 21.304 + 462 =
  22. 22.558 + 165 =
  23. 23.152 + 407 =
  24. 24.204 + 534 =
  25. 25.545 − 199 =
  26. 26.344 + 562 =
  27. 27.236 + 398 =
  28. 28.705 + 121 =
  29. 29.506 − 301 =
  30. 30.612 + 501 =
  31. 31.485 − 204 =
  32. 32.766 − 486 =
  33. 33.804 − 546 =
  34. 34.734 + 121 =
  35. 35.692 + 591 =
  36. 36.599 − 232 =
  37. 37.435 + 587 =
  38. 38.906 − 167 =
  39. 39.603 + 371 =
  40. 40.636 − 244 =

Answer key

  1. 521
  2. 317
  3. 696
  4. 970
  5. 449
  6. 721
  7. 825
  8. 518
  9. 633
  10. 375
  11. 389
  12. 498
  13. 871
  14. 545
  15. 186
  16. 656
  17. 1184
  18. 415
  19. 707
  20. 145
  21. 766
  22. 723
  23. 559
  24. 738
  25. 346
  26. 906
  27. 634
  28. 826
  29. 205
  30. 1113
  31. 281
  32. 280
  33. 258
  34. 855
  35. 1283
  36. 367
  37. 1022
  38. 739
  39. 974
  40. 392

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