← 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 506 · 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. 1.277 + 113 =
  2. 2.730 + 527 =
  3. 3.741 + 112 =
  4. 4.777 − 653 =
  5. 5.246 + 512 =
  6. 6.707 − 504 =
  7. 7.800 − 689 =
  8. 8.468 − 112 =
  9. 9.481 + 137 =
  10. 10.212 + 307 =
  11. 11.494 − 321 =
  12. 12.288 + 255 =
  13. 13.261 + 617 =
  14. 14.850 − 598 =
  15. 15.705 + 546 =
  16. 16.292 + 481 =
  17. 17.410 + 163 =
  18. 18.441 − 278 =
  19. 19.224 + 565 =
  20. 20.968 − 348 =
  21. 21.493 + 567 =
  22. 22.830 − 672 =
  23. 23.656 + 151 =
  24. 24.749 + 191 =
  25. 25.595 + 165 =
  26. 26.480 + 655 =
  27. 27.194 + 391 =
  28. 28.915 − 447 =
  29. 29.544 − 355 =
  30. 30.573 − 241 =
  31. 31.791 − 339 =
  32. 32.227 + 288 =
  33. 33.866 − 291 =
  34. 34.465 − 155 =
  35. 35.616 − 405 =
  36. 36.478 − 321 =
  37. 37.794 − 204 =
  38. 38.828 − 282 =
  39. 39.698 − 131 =
  40. 40.462 − 164 =

Answer key

  1. 390
  2. 1257
  3. 853
  4. 124
  5. 758
  6. 203
  7. 111
  8. 356
  9. 618
  10. 519
  11. 173
  12. 543
  13. 878
  14. 252
  15. 1251
  16. 773
  17. 573
  18. 163
  19. 789
  20. 620
  21. 1060
  22. 158
  23. 807
  24. 940
  25. 760
  26. 1135
  27. 585
  28. 468
  29. 189
  30. 332
  31. 452
  32. 515
  33. 575
  34. 310
  35. 211
  36. 157
  37. 590
  38. 546
  39. 567
  40. 298

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