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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 297 · 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. 1.420 − 206 =
  2. 2.348 + 534 =
  3. 3.670 − 216 =
  4. 4.547 − 154 =
  5. 5.642 − 276 =
  6. 6.719 − 208 =
  7. 7.134 + 525 =
  8. 8.871 − 164 =
  9. 9.475 + 513 =
  10. 10.462 − 223 =
  11. 11.416 + 363 =
  12. 12.665 + 226 =
  13. 13.378 + 164 =
  14. 14.350 + 149 =
  15. 15.588 − 195 =
  16. 16.592 + 554 =
  17. 17.807 − 495 =
  18. 18.352 + 331 =
  19. 19.408 + 118 =
  20. 20.649 − 404 =
  21. 21.774 − 279 =
  22. 22.563 − 461 =
  23. 23.989 − 748 =
  24. 24.242 + 487 =
  25. 25.672 + 617 =
  26. 26.596 − 364 =
  27. 27.337 + 322 =
  28. 28.576 + 562 =
  29. 29.758 + 121 =
  30. 30.487 − 219 =
  31. 31.495 − 264 =
  32. 32.284 + 345 =
  33. 33.488 − 234 =
  34. 34.639 + 134 =
  35. 35.439 − 204 =
  36. 36.745 − 311 =
  37. 37.523 + 688 =
  38. 38.322 + 643 =
  39. 39.589 − 247 =
  40. 40.159 + 631 =

Answer key

  1. 214
  2. 882
  3. 454
  4. 393
  5. 366
  6. 511
  7. 659
  8. 707
  9. 988
  10. 239
  11. 779
  12. 891
  13. 542
  14. 499
  15. 393
  16. 1146
  17. 312
  18. 683
  19. 526
  20. 245
  21. 495
  22. 102
  23. 241
  24. 729
  25. 1289
  26. 232
  27. 659
  28. 1138
  29. 879
  30. 268
  31. 231
  32. 629
  33. 254
  34. 773
  35. 235
  36. 434
  37. 1211
  38. 965
  39. 342
  40. 790

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