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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 587 · 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. 1.974 − 287 =
  2. 2.277 + 668 =
  3. 3.553 − 313 =
  4. 4.697 − 478 =
  5. 5.633 + 145 =
  6. 6.511 − 214 =
  7. 7.424 − 195 =
  8. 8.210 + 249 =
  9. 9.144 + 571 =
  10. 10.272 + 465 =
  11. 11.697 + 189 =
  12. 12.556 − 255 =
  13. 13.422 − 268 =
  14. 14.535 − 272 =
  15. 15.896 − 119 =
  16. 16.336 + 318 =
  17. 17.496 − 267 =
  18. 18.316 + 678 =
  19. 19.618 − 226 =
  20. 20.835 − 659 =
  21. 21.517 − 171 =
  22. 22.146 + 578 =
  23. 23.411 + 653 =
  24. 24.652 − 463 =
  25. 25.448 − 151 =
  26. 26.482 + 394 =
  27. 27.494 − 327 =
  28. 28.573 + 661 =
  29. 29.683 − 481 =
  30. 30.457 − 199 =
  31. 31.149 + 294 =
  32. 32.634 + 368 =
  33. 33.363 + 605 =
  34. 34.244 + 488 =
  35. 35.536 + 296 =
  36. 36.217 + 651 =
  37. 37.758 − 164 =
  38. 38.648 + 382 =
  39. 39.855 − 432 =
  40. 40.976 − 143 =

Answer key

  1. 687
  2. 945
  3. 240
  4. 219
  5. 778
  6. 297
  7. 229
  8. 459
  9. 715
  10. 737
  11. 886
  12. 301
  13. 154
  14. 263
  15. 777
  16. 654
  17. 229
  18. 994
  19. 392
  20. 176
  21. 346
  22. 724
  23. 1064
  24. 189
  25. 297
  26. 876
  27. 167
  28. 1234
  29. 202
  30. 258
  31. 443
  32. 1002
  33. 968
  34. 732
  35. 832
  36. 868
  37. 594
  38. 1030
  39. 423
  40. 833

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