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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 455 · 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. 1.720 − 233 =
  2. 2.950 − 438 =
  3. 3.639 + 365 =
  4. 4.867 − 239 =
  5. 5.663 − 371 =
  6. 6.655 − 201 =
  7. 7.353 + 139 =
  8. 8.988 − 127 =
  9. 9.762 − 191 =
  10. 10.631 + 381 =
  11. 11.462 − 118 =
  12. 12.548 − 292 =
  13. 13.242 + 682 =
  14. 14.415 + 662 =
  15. 15.368 + 643 =
  16. 16.618 − 252 =
  17. 17.852 − 734 =
  18. 18.537 + 527 =
  19. 19.412 + 329 =
  20. 20.528 − 131 =
  21. 21.528 + 471 =
  22. 22.197 + 381 =
  23. 23.490 + 257 =
  24. 24.742 + 198 =
  25. 25.253 + 207 =
  26. 26.324 + 531 =
  27. 27.527 − 385 =
  28. 28.348 + 447 =
  29. 29.238 + 247 =
  30. 30.166 + 508 =
  31. 31.724 + 536 =
  32. 32.644 + 508 =
  33. 33.699 + 643 =
  34. 34.745 − 568 =
  35. 35.415 + 422 =
  36. 36.604 − 478 =
  37. 37.193 + 267 =
  38. 38.785 + 661 =
  39. 39.493 − 302 =
  40. 40.912 − 594 =

Answer key

  1. 487
  2. 512
  3. 1004
  4. 628
  5. 292
  6. 454
  7. 492
  8. 861
  9. 571
  10. 1012
  11. 344
  12. 256
  13. 924
  14. 1077
  15. 1011
  16. 366
  17. 118
  18. 1064
  19. 741
  20. 397
  21. 999
  22. 578
  23. 747
  24. 940
  25. 460
  26. 855
  27. 142
  28. 795
  29. 485
  30. 674
  31. 1260
  32. 1152
  33. 1342
  34. 177
  35. 837
  36. 126
  37. 460
  38. 1446
  39. 191
  40. 318

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