← 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 62 · 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. 1.536 + 441 =
  2. 2.225 + 167 =
  3. 3.482 + 406 =
  4. 4.547 + 153 =
  5. 5.174 + 116 =
  6. 6.974 − 291 =
  7. 7.555 − 154 =
  8. 8.682 + 453 =
  9. 9.125 + 191 =
  10. 10.221 + 261 =
  11. 11.422 − 223 =
  12. 12.269 + 359 =
  13. 13.743 + 327 =
  14. 14.597 − 374 =
  15. 15.190 + 171 =
  16. 16.674 + 278 =
  17. 17.617 + 431 =
  18. 18.601 − 141 =
  19. 19.238 + 218 =
  20. 20.414 − 268 =
  21. 21.724 + 582 =
  22. 22.480 + 274 =
  23. 23.739 + 605 =
  24. 24.582 + 166 =
  25. 25.921 − 241 =
  26. 26.491 − 295 =
  27. 27.490 + 466 =
  28. 28.514 + 153 =
  29. 29.560 − 149 =
  30. 30.687 + 288 =
  31. 31.649 − 453 =
  32. 32.182 + 267 =
  33. 33.338 + 384 =
  34. 34.726 − 446 =
  35. 35.475 + 291 =
  36. 36.649 − 477 =
  37. 37.643 − 231 =
  38. 38.909 − 215 =
  39. 39.620 − 241 =
  40. 40.584 − 274 =

Answer key

  1. 977
  2. 392
  3. 888
  4. 700
  5. 290
  6. 683
  7. 401
  8. 1135
  9. 316
  10. 482
  11. 199
  12. 628
  13. 1070
  14. 223
  15. 361
  16. 952
  17. 1048
  18. 460
  19. 456
  20. 146
  21. 1306
  22. 754
  23. 1344
  24. 748
  25. 680
  26. 196
  27. 956
  28. 667
  29. 411
  30. 975
  31. 196
  32. 449
  33. 722
  34. 280
  35. 766
  36. 172
  37. 412
  38. 694
  39. 379
  40. 310

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