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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 59 · 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. 1.580 − 231 =
  2. 2.720 − 424 =
  3. 3.314 + 324 =
  4. 4.452 − 325 =
  5. 5.501 − 141 =
  6. 6.765 + 337 =
  7. 7.486 − 142 =
  8. 8.749 + 444 =
  9. 9.749 − 235 =
  10. 10.482 − 253 =
  11. 11.548 + 655 =
  12. 12.223 + 374 =
  13. 13.967 − 209 =
  14. 14.772 − 335 =
  15. 15.497 − 243 =
  16. 16.305 + 651 =
  17. 17.775 − 221 =
  18. 18.489 − 217 =
  19. 19.584 − 169 =
  20. 20.858 − 452 =
  21. 21.987 − 779 =
  22. 22.724 − 269 =
  23. 23.322 + 218 =
  24. 24.349 + 425 =
  25. 25.933 − 165 =
  26. 26.600 − 387 =
  27. 27.728 + 268 =
  28. 28.289 + 455 =
  29. 29.235 + 549 =
  30. 30.382 + 169 =
  31. 31.187 + 261 =
  32. 32.595 + 121 =
  33. 33.875 − 709 =
  34. 34.771 − 299 =
  35. 35.657 − 434 =
  36. 36.152 + 406 =
  37. 37.748 − 613 =
  38. 38.222 + 321 =
  39. 39.706 + 363 =
  40. 40.725 + 273 =

Answer key

  1. 349
  2. 296
  3. 638
  4. 127
  5. 360
  6. 1102
  7. 344
  8. 1193
  9. 514
  10. 229
  11. 1203
  12. 597
  13. 758
  14. 437
  15. 254
  16. 956
  17. 554
  18. 272
  19. 415
  20. 406
  21. 208
  22. 455
  23. 540
  24. 774
  25. 768
  26. 213
  27. 996
  28. 744
  29. 784
  30. 551
  31. 448
  32. 716
  33. 166
  34. 472
  35. 223
  36. 558
  37. 135
  38. 543
  39. 1069
  40. 998

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