← 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 889 · 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. 1.420 + 557 =
  2. 2.762 − 121 =
  3. 3.344 + 231 =
  4. 4.694 − 137 =
  5. 5.508 − 295 =
  6. 6.649 + 246 =
  7. 7.639 + 551 =
  8. 8.520 + 533 =
  9. 9.621 − 481 =
  10. 10.377 + 395 =
  11. 11.865 − 484 =
  12. 12.889 − 517 =
  13. 13.800 − 441 =
  14. 14.535 + 369 =
  15. 15.945 − 177 =
  16. 16.376 + 505 =
  17. 17.343 + 287 =
  18. 18.317 + 472 =
  19. 19.539 − 124 =
  20. 20.463 − 316 =
  21. 21.472 − 251 =
  22. 22.627 − 471 =
  23. 23.321 + 387 =
  24. 24.873 − 447 =
  25. 25.849 − 627 =
  26. 26.520 − 191 =
  27. 27.418 + 216 =
  28. 28.641 + 492 =
  29. 29.287 + 458 =
  30. 30.935 − 681 =
  31. 31.147 + 215 =
  32. 32.481 − 219 =
  33. 33.515 − 256 =
  34. 34.804 − 344 =
  35. 35.852 − 358 =
  36. 36.429 + 676 =
  37. 37.495 − 375 =
  38. 38.637 + 562 =
  39. 39.391 + 192 =
  40. 40.454 + 234 =

Answer key

  1. 977
  2. 641
  3. 575
  4. 557
  5. 213
  6. 895
  7. 1190
  8. 1053
  9. 140
  10. 772
  11. 381
  12. 372
  13. 359
  14. 904
  15. 768
  16. 881
  17. 630
  18. 789
  19. 415
  20. 147
  21. 221
  22. 156
  23. 708
  24. 426
  25. 222
  26. 329
  27. 634
  28. 1133
  29. 745
  30. 254
  31. 362
  32. 262
  33. 259
  34. 460
  35. 494
  36. 1105
  37. 120
  38. 1199
  39. 583
  40. 688

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