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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 777 · 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. 1.567 − 196 =
  2. 2.163 + 119 =
  3. 3.460 + 556 =
  4. 4.308 + 237 =
  5. 5.612 − 182 =
  6. 6.478 + 447 =
  7. 7.718 − 424 =
  8. 8.775 − 339 =
  9. 9.789 + 325 =
  10. 10.365 + 271 =
  11. 11.485 − 356 =
  12. 12.714 + 157 =
  13. 13.345 + 332 =
  14. 14.517 − 383 =
  15. 15.534 − 191 =
  16. 16.987 − 833 =
  17. 17.271 + 382 =
  18. 18.189 + 424 =
  19. 19.650 + 242 =
  20. 20.456 + 301 =
  21. 21.258 + 305 =
  22. 22.855 − 382 =
  23. 23.642 + 539 =
  24. 24.723 + 515 =
  25. 25.292 + 506 =
  26. 26.373 + 639 =
  27. 27.179 + 211 =
  28. 28.655 + 341 =
  29. 29.338 + 416 =
  30. 30.295 + 349 =
  31. 31.340 + 177 =
  32. 32.551 − 298 =
  33. 33.671 − 241 =
  34. 34.558 + 599 =
  35. 35.644 + 632 =
  36. 36.666 − 195 =
  37. 37.485 − 139 =
  38. 38.692 − 443 =
  39. 39.970 − 811 =
  40. 40.218 + 526 =

Answer key

  1. 371
  2. 282
  3. 1016
  4. 545
  5. 430
  6. 925
  7. 294
  8. 436
  9. 1114
  10. 636
  11. 129
  12. 871
  13. 677
  14. 134
  15. 343
  16. 154
  17. 653
  18. 613
  19. 892
  20. 757
  21. 563
  22. 473
  23. 1181
  24. 1238
  25. 798
  26. 1012
  27. 390
  28. 996
  29. 754
  30. 644
  31. 517
  32. 253
  33. 430
  34. 1157
  35. 1276
  36. 471
  37. 346
  38. 249
  39. 159
  40. 744

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