← 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 719 · 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. 1.674 − 115 =
  2. 2.325 + 662 =
  3. 3.804 − 312 =
  4. 4.440 − 266 =
  5. 5.419 − 114 =
  6. 6.258 + 195 =
  7. 7.537 + 656 =
  8. 8.790 − 492 =
  9. 9.788 + 198 =
  10. 10.509 + 631 =
  11. 11.729 + 536 =
  12. 12.534 + 599 =
  13. 13.734 + 164 =
  14. 14.577 − 179 =
  15. 15.484 − 222 =
  16. 16.778 + 164 =
  17. 17.585 + 281 =
  18. 18.903 − 572 =
  19. 19.655 + 218 =
  20. 20.524 − 178 =
  21. 21.510 − 299 =
  22. 22.634 − 173 =
  23. 23.740 + 265 =
  24. 24.431 + 216 =
  25. 25.860 − 245 =
  26. 26.674 + 187 =
  27. 27.726 − 196 =
  28. 28.673 + 332 =
  29. 29.149 + 206 =
  30. 30.664 − 194 =
  31. 31.973 − 541 =
  32. 32.679 + 285 =
  33. 33.564 − 464 =
  34. 34.322 + 551 =
  35. 35.615 − 281 =
  36. 36.374 + 287 =
  37. 37.522 − 313 =
  38. 38.434 − 331 =
  39. 39.429 − 145 =
  40. 40.754 − 602 =

Answer key

  1. 559
  2. 987
  3. 492
  4. 174
  5. 305
  6. 453
  7. 1193
  8. 298
  9. 986
  10. 1140
  11. 1265
  12. 1133
  13. 898
  14. 398
  15. 262
  16. 942
  17. 866
  18. 331
  19. 873
  20. 346
  21. 211
  22. 461
  23. 1005
  24. 647
  25. 615
  26. 861
  27. 530
  28. 1005
  29. 355
  30. 470
  31. 432
  32. 964
  33. 100
  34. 873
  35. 334
  36. 661
  37. 209
  38. 103
  39. 284
  40. 152

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