← 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 841 · 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. 1.509 − 301 =
  2. 2.313 + 426 =
  3. 3.462 + 252 =
  4. 4.391 + 356 =
  5. 5.148 + 265 =
  6. 6.142 + 271 =
  7. 7.981 − 767 =
  8. 8.679 + 648 =
  9. 9.250 + 441 =
  10. 10.929 − 308 =
  11. 11.606 + 181 =
  12. 12.958 − 206 =
  13. 13.615 − 292 =
  14. 14.275 + 482 =
  15. 15.713 − 583 =
  16. 16.287 + 208 =
  17. 17.498 − 148 =
  18. 18.467 + 515 =
  19. 19.309 + 565 =
  20. 20.673 − 346 =
  21. 21.626 + 561 =
  22. 22.631 − 325 =
  23. 23.709 − 485 =
  24. 24.783 + 154 =
  25. 25.984 − 334 =
  26. 26.151 + 393 =
  27. 27.314 + 462 =
  28. 28.678 + 273 =
  29. 29.184 + 353 =
  30. 30.551 + 684 =
  31. 31.820 − 394 =
  32. 32.210 + 206 =
  33. 33.567 − 221 =
  34. 34.373 + 388 =
  35. 35.652 − 305 =
  36. 36.440 + 319 =
  37. 37.421 + 461 =
  38. 38.548 + 212 =
  39. 39.540 − 117 =
  40. 40.217 + 257 =

Answer key

  1. 208
  2. 739
  3. 714
  4. 747
  5. 413
  6. 413
  7. 214
  8. 1327
  9. 691
  10. 621
  11. 787
  12. 752
  13. 323
  14. 757
  15. 130
  16. 495
  17. 350
  18. 982
  19. 874
  20. 327
  21. 1187
  22. 306
  23. 224
  24. 937
  25. 650
  26. 544
  27. 776
  28. 951
  29. 537
  30. 1235
  31. 426
  32. 416
  33. 346
  34. 761
  35. 347
  36. 759
  37. 882
  38. 760
  39. 423
  40. 474

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