← 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 511 · 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. 1.310 + 517 =
  2. 2.214 + 201 =
  3. 3.867 − 662 =
  4. 4.343 + 596 =
  5. 5.529 + 678 =
  6. 6.448 + 683 =
  7. 7.139 + 463 =
  8. 8.619 − 459 =
  9. 9.892 − 216 =
  10. 10.595 + 201 =
  11. 11.585 + 494 =
  12. 12.542 − 261 =
  13. 13.691 − 495 =
  14. 14.632 − 283 =
  15. 15.685 − 198 =
  16. 16.142 + 172 =
  17. 17.498 − 241 =
  18. 18.905 − 386 =
  19. 19.145 + 211 =
  20. 20.257 + 248 =
  21. 21.475 − 311 =
  22. 22.727 + 353 =
  23. 23.691 − 499 =
  24. 24.462 − 317 =
  25. 25.280 + 535 =
  26. 26.535 + 188 =
  27. 27.604 − 278 =
  28. 28.504 − 167 =
  29. 29.392 + 186 =
  30. 30.441 + 599 =
  31. 31.715 + 426 =
  32. 32.866 − 183 =
  33. 33.418 + 332 =
  34. 34.667 − 291 =
  35. 35.503 − 178 =
  36. 36.500 − 374 =
  37. 37.298 + 458 =
  38. 38.583 − 156 =
  39. 39.580 + 579 =
  40. 40.629 − 203 =

Answer key

  1. 827
  2. 415
  3. 205
  4. 939
  5. 1207
  6. 1131
  7. 602
  8. 160
  9. 676
  10. 796
  11. 1079
  12. 281
  13. 196
  14. 349
  15. 487
  16. 314
  17. 257
  18. 519
  19. 356
  20. 505
  21. 164
  22. 1080
  23. 192
  24. 145
  25. 815
  26. 723
  27. 326
  28. 337
  29. 578
  30. 1040
  31. 1141
  32. 683
  33. 750
  34. 376
  35. 325
  36. 126
  37. 756
  38. 427
  39. 1159
  40. 426

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