← Add and subtract 3-digit numbers left to right lesson New set →

3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 64 · 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. 1.138 + 395 =
  2. 2.193 + 195 =
  3. 3.550 + 223 =
  4. 4.335 + 662 =
  5. 5.349 + 625 =
  6. 6.934 − 736 =
  7. 7.353 + 632 =
  8. 8.333 + 398 =
  9. 9.867 − 542 =
  10. 10.923 − 309 =
  11. 11.867 − 264 =
  12. 12.508 + 281 =
  13. 13.637 + 204 =
  14. 14.671 − 521 =
  15. 15.734 − 564 =
  16. 16.682 + 272 =
  17. 17.304 + 556 =
  18. 18.527 + 688 =
  19. 19.486 − 136 =
  20. 20.702 + 251 =
  21. 21.212 + 314 =
  22. 22.960 − 239 =
  23. 23.834 − 719 =
  24. 24.550 − 121 =
  25. 25.567 − 424 =
  26. 26.544 + 383 =
  27. 27.277 + 196 =
  28. 28.594 − 153 =
  29. 29.638 + 544 =
  30. 30.354 + 228 =
  31. 31.709 + 576 =
  32. 32.369 + 202 =
  33. 33.659 − 486 =
  34. 34.843 − 478 =
  35. 35.547 + 667 =
  36. 36.665 + 422 =
  37. 37.305 + 685 =
  38. 38.364 + 641 =
  39. 39.299 + 144 =
  40. 40.628 + 278 =

Answer key

  1. 533
  2. 388
  3. 773
  4. 997
  5. 974
  6. 198
  7. 985
  8. 731
  9. 325
  10. 614
  11. 603
  12. 789
  13. 841
  14. 150
  15. 170
  16. 954
  17. 860
  18. 1215
  19. 350
  20. 953
  21. 526
  22. 721
  23. 115
  24. 429
  25. 143
  26. 927
  27. 473
  28. 441
  29. 1182
  30. 582
  31. 1285
  32. 571
  33. 173
  34. 365
  35. 1214
  36. 1087
  37. 990
  38. 1005
  39. 443
  40. 906

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths