← 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 768 · 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. 1.478 − 339 =
  2. 2.290 + 183 =
  3. 3.400 + 577 =
  4. 4.193 + 685 =
  5. 5.771 + 361 =
  6. 6.579 + 246 =
  7. 7.774 − 313 =
  8. 8.568 − 261 =
  9. 9.370 + 546 =
  10. 10.646 + 356 =
  11. 11.625 − 198 =
  12. 12.717 + 488 =
  13. 13.517 − 186 =
  14. 14.466 + 237 =
  15. 15.602 + 204 =
  16. 16.533 − 341 =
  17. 17.220 + 476 =
  18. 18.332 + 597 =
  19. 19.524 + 117 =
  20. 20.450 + 173 =
  21. 21.750 + 113 =
  22. 22.503 − 121 =
  23. 23.131 + 381 =
  24. 24.459 + 651 =
  25. 25.636 + 281 =
  26. 26.462 − 261 =
  27. 27.264 + 301 =
  28. 28.170 + 119 =
  29. 29.423 − 212 =
  30. 30.450 + 305 =
  31. 31.766 − 534 =
  32. 32.598 + 631 =
  33. 33.509 + 261 =
  34. 34.459 + 231 =
  35. 35.241 + 416 =
  36. 36.427 − 117 =
  37. 37.444 − 219 =
  38. 38.935 − 505 =
  39. 39.976 − 192 =
  40. 40.253 + 441 =

Answer key

  1. 139
  2. 473
  3. 977
  4. 878
  5. 1132
  6. 825
  7. 461
  8. 307
  9. 916
  10. 1002
  11. 427
  12. 1205
  13. 331
  14. 703
  15. 806
  16. 192
  17. 696
  18. 929
  19. 641
  20. 623
  21. 863
  22. 382
  23. 512
  24. 1110
  25. 917
  26. 201
  27. 565
  28. 289
  29. 211
  30. 755
  31. 232
  32. 1229
  33. 770
  34. 690
  35. 657
  36. 310
  37. 225
  38. 430
  39. 784
  40. 694

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