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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 117 · 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. 1.498 − 362 =
  2. 2.543 + 435 =
  3. 3.522 + 481 =
  4. 4.565 − 153 =
  5. 5.387 + 146 =
  6. 6.581 + 527 =
  7. 7.132 + 218 =
  8. 8.866 − 151 =
  9. 9.539 − 349 =
  10. 10.649 − 443 =
  11. 11.840 − 641 =
  12. 12.150 + 531 =
  13. 13.501 − 133 =
  14. 14.300 + 677 =
  15. 15.358 + 137 =
  16. 16.569 + 177 =
  17. 17.419 + 211 =
  18. 18.911 − 404 =
  19. 19.258 + 627 =
  20. 20.545 + 167 =
  21. 21.819 − 525 =
  22. 22.523 + 595 =
  23. 23.544 − 153 =
  24. 24.878 − 516 =
  25. 25.125 + 426 =
  26. 26.569 − 201 =
  27. 27.265 + 666 =
  28. 28.612 + 678 =
  29. 29.253 + 639 =
  30. 30.823 − 175 =
  31. 31.682 + 201 =
  32. 32.126 + 141 =
  33. 33.312 + 264 =
  34. 34.761 − 341 =
  35. 35.276 + 388 =
  36. 36.236 + 142 =
  37. 37.432 + 416 =
  38. 38.539 − 146 =
  39. 39.469 − 331 =
  40. 40.310 + 427 =

Answer key

  1. 136
  2. 978
  3. 1003
  4. 412
  5. 533
  6. 1108
  7. 350
  8. 715
  9. 190
  10. 206
  11. 199
  12. 681
  13. 368
  14. 977
  15. 495
  16. 746
  17. 630
  18. 507
  19. 885
  20. 712
  21. 294
  22. 1118
  23. 391
  24. 362
  25. 551
  26. 368
  27. 931
  28. 1290
  29. 892
  30. 648
  31. 883
  32. 267
  33. 576
  34. 420
  35. 664
  36. 378
  37. 848
  38. 393
  39. 138
  40. 737

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