← 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 460 · 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. 1.987 − 212 =
  2. 2.789 + 634 =
  3. 3.544 + 256 =
  4. 4.768 − 252 =
  5. 5.425 − 325 =
  6. 6.375 + 582 =
  7. 7.674 − 521 =
  8. 8.764 + 362 =
  9. 9.357 + 491 =
  10. 10.450 − 136 =
  11. 11.301 + 208 =
  12. 12.730 − 376 =
  13. 13.181 + 501 =
  14. 14.653 − 189 =
  15. 15.415 + 547 =
  16. 16.763 − 288 =
  17. 17.678 + 658 =
  18. 18.522 − 414 =
  19. 19.699 − 159 =
  20. 20.796 − 208 =
  21. 21.609 − 446 =
  22. 22.492 − 281 =
  23. 23.804 − 571 =
  24. 24.918 − 178 =
  25. 25.124 + 596 =
  26. 26.780 − 131 =
  27. 27.838 − 518 =
  28. 28.685 − 506 =
  29. 29.616 − 431 =
  30. 30.212 + 371 =
  31. 31.653 + 339 =
  32. 32.965 − 479 =
  33. 33.476 − 234 =
  34. 34.434 − 152 =
  35. 35.647 − 508 =
  36. 36.345 + 581 =
  37. 37.875 − 313 =
  38. 38.812 − 358 =
  39. 39.908 − 792 =
  40. 40.528 + 677 =

Answer key

  1. 775
  2. 1423
  3. 800
  4. 516
  5. 100
  6. 957
  7. 153
  8. 1126
  9. 848
  10. 314
  11. 509
  12. 354
  13. 682
  14. 464
  15. 962
  16. 475
  17. 1336
  18. 108
  19. 540
  20. 588
  21. 163
  22. 211
  23. 233
  24. 740
  25. 720
  26. 649
  27. 320
  28. 179
  29. 185
  30. 583
  31. 992
  32. 486
  33. 242
  34. 282
  35. 139
  36. 926
  37. 562
  38. 454
  39. 116
  40. 1205

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