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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 516 · 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. 1.561 − 223 =
  2. 2.213 + 534 =
  3. 3.861 − 202 =
  4. 4.728 − 627 =
  5. 5.944 − 769 =
  6. 6.782 − 181 =
  7. 7.281 + 196 =
  8. 8.504 + 189 =
  9. 9.138 + 392 =
  10. 10.785 + 689 =
  11. 11.264 + 401 =
  12. 12.896 − 432 =
  13. 13.870 − 687 =
  14. 14.424 − 172 =
  15. 15.640 + 392 =
  16. 16.261 + 418 =
  17. 17.187 + 505 =
  18. 18.848 − 333 =
  19. 19.246 + 165 =
  20. 20.786 − 441 =
  21. 21.453 − 225 =
  22. 22.722 + 202 =
  23. 23.810 − 453 =
  24. 24.177 + 653 =
  25. 25.208 + 431 =
  26. 26.379 + 252 =
  27. 27.431 − 115 =
  28. 28.492 − 294 =
  29. 29.383 + 522 =
  30. 30.553 + 412 =
  31. 31.361 + 421 =
  32. 32.463 + 146 =
  33. 33.936 − 295 =
  34. 34.464 + 642 =
  35. 35.855 − 492 =
  36. 36.529 + 437 =
  37. 37.505 + 147 =
  38. 38.126 + 467 =
  39. 39.135 + 631 =
  40. 40.344 + 385 =

Answer key

  1. 338
  2. 747
  3. 659
  4. 101
  5. 175
  6. 601
  7. 477
  8. 693
  9. 530
  10. 1474
  11. 665
  12. 464
  13. 183
  14. 252
  15. 1032
  16. 679
  17. 692
  18. 515
  19. 411
  20. 345
  21. 228
  22. 924
  23. 357
  24. 830
  25. 639
  26. 631
  27. 316
  28. 198
  29. 905
  30. 965
  31. 782
  32. 609
  33. 641
  34. 1106
  35. 363
  36. 966
  37. 652
  38. 593
  39. 766
  40. 729

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