← 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 928 · 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. 1.323 + 443 =
  2. 2.464 + 149 =
  3. 3.371 + 479 =
  4. 4.739 + 336 =
  5. 5.371 + 325 =
  6. 6.609 − 466 =
  7. 7.156 + 421 =
  8. 8.432 − 181 =
  9. 9.539 − 317 =
  10. 10.558 − 168 =
  11. 11.206 + 315 =
  12. 12.699 + 581 =
  13. 13.746 − 641 =
  14. 14.658 − 188 =
  15. 15.531 − 161 =
  16. 16.266 + 627 =
  17. 17.163 + 384 =
  18. 18.653 − 156 =
  19. 19.877 − 344 =
  20. 20.209 + 157 =
  21. 21.459 − 133 =
  22. 22.835 − 251 =
  23. 23.540 + 264 =
  24. 24.346 + 567 =
  25. 25.758 − 504 =
  26. 26.660 − 366 =
  27. 27.252 + 179 =
  28. 28.488 − 349 =
  29. 29.750 − 616 =
  30. 30.263 + 395 =
  31. 31.219 + 669 =
  32. 32.852 − 594 =
  33. 33.268 + 624 =
  34. 34.452 − 125 =
  35. 35.179 + 259 =
  36. 36.620 + 406 =
  37. 37.441 − 293 =
  38. 38.443 + 346 =
  39. 39.938 − 623 =
  40. 40.474 + 664 =

Answer key

  1. 766
  2. 613
  3. 850
  4. 1075
  5. 696
  6. 143
  7. 577
  8. 251
  9. 222
  10. 390
  11. 521
  12. 1280
  13. 105
  14. 470
  15. 370
  16. 893
  17. 547
  18. 497
  19. 533
  20. 366
  21. 326
  22. 584
  23. 804
  24. 913
  25. 254
  26. 294
  27. 431
  28. 139
  29. 134
  30. 658
  31. 888
  32. 258
  33. 892
  34. 327
  35. 438
  36. 1026
  37. 148
  38. 789
  39. 315
  40. 1138

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