← 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 626 · 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. 1.483 − 156 =
  2. 2.428 + 242 =
  3. 3.496 − 145 =
  4. 4.475 − 158 =
  5. 5.264 + 148 =
  6. 6.460 + 207 =
  7. 7.487 + 116 =
  8. 8.210 + 211 =
  9. 9.699 + 545 =
  10. 10.423 + 234 =
  11. 11.647 + 237 =
  12. 12.646 − 239 =
  13. 13.939 − 308 =
  14. 14.161 + 548 =
  15. 15.318 + 414 =
  16. 16.492 + 244 =
  17. 17.658 + 333 =
  18. 18.209 + 148 =
  19. 19.953 − 167 =
  20. 20.522 + 229 =
  21. 21.752 − 302 =
  22. 22.747 + 612 =
  23. 23.652 − 394 =
  24. 24.270 + 688 =
  25. 25.619 − 511 =
  26. 26.602 − 196 =
  27. 27.878 − 737 =
  28. 28.966 − 444 =
  29. 29.154 + 674 =
  30. 30.692 + 551 =
  31. 31.457 + 653 =
  32. 32.712 + 611 =
  33. 33.262 + 627 =
  34. 34.181 + 241 =
  35. 35.957 − 642 =
  36. 36.188 + 434 =
  37. 37.596 − 452 =
  38. 38.130 + 196 =
  39. 39.416 − 121 =
  40. 40.957 − 165 =

Answer key

  1. 327
  2. 670
  3. 351
  4. 317
  5. 412
  6. 667
  7. 603
  8. 421
  9. 1244
  10. 657
  11. 884
  12. 407
  13. 631
  14. 709
  15. 732
  16. 736
  17. 991
  18. 357
  19. 786
  20. 751
  21. 450
  22. 1359
  23. 258
  24. 958
  25. 108
  26. 406
  27. 141
  28. 522
  29. 828
  30. 1243
  31. 1110
  32. 1323
  33. 889
  34. 422
  35. 315
  36. 622
  37. 144
  38. 326
  39. 295
  40. 792

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