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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 419 · 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. 1.132 + 358 =
  2. 2.961 − 741 =
  3. 3.839 − 212 =
  4. 4.206 + 429 =
  5. 5.963 − 537 =
  6. 6.805 − 135 =
  7. 7.192 + 391 =
  8. 8.623 − 492 =
  9. 9.454 − 318 =
  10. 10.627 − 381 =
  11. 11.465 − 149 =
  12. 12.396 + 292 =
  13. 13.304 + 351 =
  14. 14.782 − 112 =
  15. 15.529 + 468 =
  16. 16.233 + 568 =
  17. 17.663 − 272 =
  18. 18.481 + 229 =
  19. 19.656 − 231 =
  20. 20.275 + 379 =
  21. 21.923 − 306 =
  22. 22.147 + 657 =
  23. 23.852 − 136 =
  24. 24.489 + 113 =
  25. 25.145 + 324 =
  26. 26.590 + 682 =
  27. 27.710 − 537 =
  28. 28.857 − 736 =
  29. 29.782 − 201 =
  30. 30.507 + 535 =
  31. 31.944 − 825 =
  32. 32.736 + 478 =
  33. 33.714 − 309 =
  34. 34.616 − 242 =
  35. 35.578 + 121 =
  36. 36.974 − 185 =
  37. 37.558 − 114 =
  38. 38.456 + 206 =
  39. 39.330 + 559 =
  40. 40.227 + 203 =

Answer key

  1. 490
  2. 220
  3. 627
  4. 635
  5. 426
  6. 670
  7. 583
  8. 131
  9. 136
  10. 246
  11. 316
  12. 688
  13. 655
  14. 670
  15. 997
  16. 801
  17. 391
  18. 710
  19. 425
  20. 654
  21. 617
  22. 804
  23. 716
  24. 602
  25. 469
  26. 1272
  27. 173
  28. 121
  29. 581
  30. 1042
  31. 119
  32. 1214
  33. 405
  34. 374
  35. 699
  36. 789
  37. 444
  38. 662
  39. 889
  40. 430

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