← 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 936 · 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. 1.216 + 452 =
  2. 2.440 + 302 =
  3. 3.876 − 139 =
  4. 4.598 − 471 =
  5. 5.725 − 555 =
  6. 6.323 + 131 =
  7. 7.577 + 605 =
  8. 8.346 + 287 =
  9. 9.881 − 181 =
  10. 10.335 + 563 =
  11. 11.359 + 361 =
  12. 12.244 + 312 =
  13. 13.143 + 257 =
  14. 14.520 − 344 =
  15. 15.586 + 418 =
  16. 16.829 − 547 =
  17. 17.184 + 556 =
  18. 18.934 − 405 =
  19. 19.466 − 292 =
  20. 20.815 − 454 =
  21. 21.560 + 464 =
  22. 22.243 + 145 =
  23. 23.846 − 241 =
  24. 24.641 − 205 =
  25. 25.520 − 232 =
  26. 26.503 − 141 =
  27. 27.237 + 523 =
  28. 28.718 − 116 =
  29. 29.627 + 325 =
  30. 30.516 − 199 =
  31. 31.749 + 593 =
  32. 32.432 + 271 =
  33. 33.126 + 194 =
  34. 34.689 + 128 =
  35. 35.655 + 296 =
  36. 36.630 + 555 =
  37. 37.743 − 428 =
  38. 38.307 + 169 =
  39. 39.273 + 371 =
  40. 40.623 + 429 =

Answer key

  1. 668
  2. 742
  3. 737
  4. 127
  5. 170
  6. 454
  7. 1182
  8. 633
  9. 700
  10. 898
  11. 720
  12. 556
  13. 400
  14. 176
  15. 1004
  16. 282
  17. 740
  18. 529
  19. 174
  20. 361
  21. 1024
  22. 388
  23. 605
  24. 436
  25. 288
  26. 362
  27. 760
  28. 602
  29. 952
  30. 317
  31. 1342
  32. 703
  33. 320
  34. 817
  35. 951
  36. 1185
  37. 315
  38. 476
  39. 644
  40. 1052

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