← 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 86 · 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. 1.241 + 537 =
  2. 2.638 + 175 =
  3. 3.879 − 667 =
  4. 4.554 − 304 =
  5. 5.939 − 421 =
  6. 6.184 + 261 =
  7. 7.892 − 534 =
  8. 8.919 − 711 =
  9. 9.577 − 329 =
  10. 10.460 − 147 =
  11. 11.293 + 683 =
  12. 12.504 − 246 =
  13. 13.663 − 214 =
  14. 14.822 − 173 =
  15. 15.642 + 204 =
  16. 16.727 − 122 =
  17. 17.133 + 556 =
  18. 18.162 + 138 =
  19. 19.869 − 459 =
  20. 20.553 − 431 =
  21. 21.380 + 608 =
  22. 22.785 + 195 =
  23. 23.665 + 366 =
  24. 24.713 − 508 =
  25. 25.479 + 656 =
  26. 26.153 + 551 =
  27. 27.654 + 356 =
  28. 28.489 + 137 =
  29. 29.500 + 474 =
  30. 30.973 − 723 =
  31. 31.789 + 545 =
  32. 32.137 + 358 =
  33. 33.297 + 611 =
  34. 34.708 − 205 =
  35. 35.431 − 214 =
  36. 36.494 − 304 =
  37. 37.181 + 454 =
  38. 38.658 − 376 =
  39. 39.577 − 199 =
  40. 40.640 + 142 =

Answer key

  1. 778
  2. 813
  3. 212
  4. 250
  5. 518
  6. 445
  7. 358
  8. 208
  9. 248
  10. 313
  11. 976
  12. 258
  13. 449
  14. 649
  15. 846
  16. 605
  17. 689
  18. 300
  19. 410
  20. 122
  21. 988
  22. 980
  23. 1031
  24. 205
  25. 1135
  26. 704
  27. 1010
  28. 626
  29. 974
  30. 250
  31. 1334
  32. 495
  33. 908
  34. 503
  35. 217
  36. 190
  37. 635
  38. 282
  39. 378
  40. 782

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