← 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 660 · 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. 1.617 + 282 =
  2. 2.156 + 671 =
  3. 3.904 − 228 =
  4. 4.132 + 472 =
  5. 5.504 + 591 =
  6. 6.863 − 511 =
  7. 7.762 + 682 =
  8. 8.478 + 403 =
  9. 9.283 + 138 =
  10. 10.646 − 457 =
  11. 11.245 + 133 =
  12. 12.616 + 218 =
  13. 13.607 − 374 =
  14. 14.850 − 535 =
  15. 15.888 − 275 =
  16. 16.734 + 292 =
  17. 17.308 + 682 =
  18. 18.459 − 121 =
  19. 19.288 + 626 =
  20. 20.330 + 129 =
  21. 21.769 − 291 =
  22. 22.745 + 213 =
  23. 23.600 + 121 =
  24. 24.943 − 241 =
  25. 25.485 − 308 =
  26. 26.919 − 424 =
  27. 27.556 − 355 =
  28. 28.907 − 572 =
  29. 29.341 + 222 =
  30. 30.782 − 429 =
  31. 31.589 + 595 =
  32. 32.222 + 441 =
  33. 33.198 + 341 =
  34. 34.528 + 332 =
  35. 35.444 + 248 =
  36. 36.724 − 564 =
  37. 37.246 + 401 =
  38. 38.766 + 676 =
  39. 39.259 + 381 =
  40. 40.271 + 228 =

Answer key

  1. 899
  2. 827
  3. 676
  4. 604
  5. 1095
  6. 352
  7. 1444
  8. 881
  9. 421
  10. 189
  11. 378
  12. 834
  13. 233
  14. 315
  15. 613
  16. 1026
  17. 990
  18. 338
  19. 914
  20. 459
  21. 478
  22. 958
  23. 721
  24. 702
  25. 177
  26. 495
  27. 201
  28. 335
  29. 563
  30. 353
  31. 1184
  32. 663
  33. 539
  34. 860
  35. 692
  36. 160
  37. 647
  38. 1442
  39. 640
  40. 499

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