← 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 893 · 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. 1.660 − 322 =
  2. 2.585 − 324 =
  3. 3.398 + 161 =
  4. 4.879 − 613 =
  5. 5.308 + 635 =
  6. 6.275 + 602 =
  7. 7.583 + 302 =
  8. 8.691 + 421 =
  9. 9.861 − 201 =
  10. 10.973 − 421 =
  11. 11.604 + 134 =
  12. 12.133 + 121 =
  13. 13.540 + 135 =
  14. 14.445 − 315 =
  15. 15.919 − 761 =
  16. 16.717 − 474 =
  17. 17.680 − 482 =
  18. 18.719 − 413 =
  19. 19.400 + 647 =
  20. 20.942 − 441 =
  21. 21.404 + 394 =
  22. 22.958 − 186 =
  23. 23.766 − 123 =
  24. 24.898 − 627 =
  25. 25.912 − 689 =
  26. 26.519 + 251 =
  27. 27.720 + 621 =
  28. 28.577 + 521 =
  29. 29.640 + 471 =
  30. 30.211 + 283 =
  31. 31.549 − 163 =
  32. 32.453 + 455 =
  33. 33.843 − 732 =
  34. 34.873 − 493 =
  35. 35.885 − 292 =
  36. 36.596 + 513 =
  37. 37.458 − 309 =
  38. 38.496 − 213 =
  39. 39.481 + 235 =
  40. 40.470 − 161 =

Answer key

  1. 338
  2. 261
  3. 559
  4. 266
  5. 943
  6. 877
  7. 885
  8. 1112
  9. 660
  10. 552
  11. 738
  12. 254
  13. 675
  14. 130
  15. 158
  16. 243
  17. 198
  18. 306
  19. 1047
  20. 501
  21. 798
  22. 772
  23. 643
  24. 271
  25. 223
  26. 770
  27. 1341
  28. 1098
  29. 1111
  30. 494
  31. 386
  32. 908
  33. 111
  34. 380
  35. 593
  36. 1109
  37. 149
  38. 283
  39. 716
  40. 309

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