← 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 385 · 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. 1.629 + 391 =
  2. 2.771 + 319 =
  3. 3.533 − 158 =
  4. 4.519 − 344 =
  5. 5.537 + 551 =
  6. 6.977 − 233 =
  7. 7.894 − 315 =
  8. 8.166 + 152 =
  9. 9.766 + 448 =
  10. 10.589 + 512 =
  11. 11.576 − 221 =
  12. 12.411 + 468 =
  13. 13.569 + 646 =
  14. 14.470 + 621 =
  15. 15.880 − 693 =
  16. 16.150 + 204 =
  17. 17.643 − 171 =
  18. 18.232 + 259 =
  19. 19.434 + 159 =
  20. 20.201 + 499 =
  21. 21.436 − 169 =
  22. 22.298 + 341 =
  23. 23.538 + 345 =
  24. 24.763 − 112 =
  25. 25.600 + 623 =
  26. 26.980 − 713 =
  27. 27.312 + 683 =
  28. 28.619 + 555 =
  29. 29.617 + 122 =
  30. 30.547 − 348 =
  31. 31.546 + 271 =
  32. 32.613 + 191 =
  33. 33.451 + 391 =
  34. 34.939 − 336 =
  35. 35.275 + 186 =
  36. 36.853 − 752 =
  37. 37.679 + 413 =
  38. 38.704 − 188 =
  39. 39.213 + 484 =
  40. 40.626 + 301 =

Answer key

  1. 1020
  2. 1090
  3. 375
  4. 175
  5. 1088
  6. 744
  7. 579
  8. 318
  9. 1214
  10. 1101
  11. 355
  12. 879
  13. 1215
  14. 1091
  15. 187
  16. 354
  17. 472
  18. 491
  19. 593
  20. 700
  21. 267
  22. 639
  23. 883
  24. 651
  25. 1223
  26. 267
  27. 995
  28. 1174
  29. 739
  30. 199
  31. 817
  32. 804
  33. 842
  34. 603
  35. 461
  36. 101
  37. 1092
  38. 516
  39. 697
  40. 927

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