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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 792 · 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. 1.469 − 181 =
  2. 2.397 + 191 =
  3. 3.757 + 241 =
  4. 4.414 − 201 =
  5. 5.692 + 296 =
  6. 6.747 + 303 =
  7. 7.984 − 695 =
  8. 8.526 + 318 =
  9. 9.812 − 181 =
  10. 10.631 − 254 =
  11. 11.414 + 293 =
  12. 12.753 − 592 =
  13. 13.203 + 147 =
  14. 14.248 + 112 =
  15. 15.628 − 155 =
  16. 16.822 − 181 =
  17. 17.845 − 327 =
  18. 18.636 + 147 =
  19. 19.516 − 158 =
  20. 20.618 + 139 =
  21. 21.701 − 243 =
  22. 22.306 + 663 =
  23. 23.583 − 341 =
  24. 24.267 + 629 =
  25. 25.416 + 468 =
  26. 26.561 + 487 =
  27. 27.307 + 542 =
  28. 28.138 + 506 =
  29. 29.869 − 474 =
  30. 30.645 + 681 =
  31. 31.685 − 415 =
  32. 32.967 − 381 =
  33. 33.920 − 298 =
  34. 34.588 + 132 =
  35. 35.692 − 188 =
  36. 36.377 + 605 =
  37. 37.590 + 631 =
  38. 38.588 + 151 =
  39. 39.718 + 163 =
  40. 40.133 + 165 =

Answer key

  1. 288
  2. 588
  3. 998
  4. 213
  5. 988
  6. 1050
  7. 289
  8. 844
  9. 631
  10. 377
  11. 707
  12. 161
  13. 350
  14. 360
  15. 473
  16. 641
  17. 518
  18. 783
  19. 358
  20. 757
  21. 458
  22. 969
  23. 242
  24. 896
  25. 884
  26. 1048
  27. 849
  28. 644
  29. 395
  30. 1326
  31. 270
  32. 586
  33. 622
  34. 720
  35. 504
  36. 982
  37. 1221
  38. 739
  39. 881
  40. 298

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