← 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 921 · 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. 1.200 + 467 =
  2. 2.971 − 532 =
  3. 3.316 + 346 =
  4. 4.694 + 539 =
  5. 5.540 − 271 =
  6. 6.255 + 217 =
  7. 7.603 − 429 =
  8. 8.208 + 329 =
  9. 9.432 + 434 =
  10. 10.612 + 243 =
  11. 11.470 − 241 =
  12. 12.610 + 125 =
  13. 13.623 − 523 =
  14. 14.141 + 288 =
  15. 15.909 − 664 =
  16. 16.583 − 261 =
  17. 17.693 − 412 =
  18. 18.229 + 454 =
  19. 19.144 + 461 =
  20. 20.221 + 521 =
  21. 21.782 + 592 =
  22. 22.598 − 225 =
  23. 23.463 + 669 =
  24. 24.762 + 126 =
  25. 25.483 − 213 =
  26. 26.414 − 246 =
  27. 27.300 + 118 =
  28. 28.491 + 139 =
  29. 29.560 + 581 =
  30. 30.794 − 211 =
  31. 31.730 + 678 =
  32. 32.724 + 474 =
  33. 33.358 + 316 =
  34. 34.422 + 178 =
  35. 35.606 + 326 =
  36. 36.563 + 615 =
  37. 37.706 + 581 =
  38. 38.444 − 222 =
  39. 39.368 + 191 =
  40. 40.130 + 167 =

Answer key

  1. 667
  2. 439
  3. 662
  4. 1233
  5. 269
  6. 472
  7. 174
  8. 537
  9. 866
  10. 855
  11. 229
  12. 735
  13. 100
  14. 429
  15. 245
  16. 322
  17. 281
  18. 683
  19. 605
  20. 742
  21. 1374
  22. 373
  23. 1132
  24. 888
  25. 270
  26. 168
  27. 418
  28. 630
  29. 1141
  30. 583
  31. 1408
  32. 1198
  33. 674
  34. 600
  35. 932
  36. 1178
  37. 1287
  38. 222
  39. 559
  40. 297

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