← 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 269 · 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. 1.860 − 175 =
  2. 2.416 − 141 =
  3. 3.759 + 558 =
  4. 4.562 + 406 =
  5. 5.483 + 199 =
  6. 6.517 − 207 =
  7. 7.125 + 306 =
  8. 8.350 + 212 =
  9. 9.888 − 527 =
  10. 10.313 + 248 =
  11. 11.956 − 536 =
  12. 12.538 − 246 =
  13. 13.755 − 297 =
  14. 14.763 + 665 =
  15. 15.553 + 651 =
  16. 16.601 − 359 =
  17. 17.478 − 114 =
  18. 18.508 − 396 =
  19. 19.571 + 298 =
  20. 20.820 − 515 =
  21. 21.946 − 465 =
  22. 22.689 + 645 =
  23. 23.895 − 686 =
  24. 24.428 − 286 =
  25. 25.228 + 292 =
  26. 26.152 + 631 =
  27. 27.494 − 305 =
  28. 28.223 + 391 =
  29. 29.808 − 169 =
  30. 30.185 + 232 =
  31. 31.684 − 522 =
  32. 32.988 − 222 =
  33. 33.728 − 238 =
  34. 34.686 + 681 =
  35. 35.725 + 536 =
  36. 36.660 − 484 =
  37. 37.302 + 431 =
  38. 38.194 + 532 =
  39. 39.261 + 455 =
  40. 40.520 − 166 =

Answer key

  1. 685
  2. 275
  3. 1317
  4. 968
  5. 682
  6. 310
  7. 431
  8. 562
  9. 361
  10. 561
  11. 420
  12. 292
  13. 458
  14. 1428
  15. 1204
  16. 242
  17. 364
  18. 112
  19. 869
  20. 305
  21. 481
  22. 1334
  23. 209
  24. 142
  25. 520
  26. 783
  27. 189
  28. 614
  29. 639
  30. 417
  31. 162
  32. 766
  33. 490
  34. 1367
  35. 1261
  36. 176
  37. 733
  38. 726
  39. 716
  40. 354

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