← 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 530 · 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. 1.792 − 669 =
  2. 2.519 − 247 =
  3. 3.664 − 147 =
  4. 4.484 + 124 =
  5. 5.631 − 291 =
  6. 6.877 − 533 =
  7. 7.556 − 417 =
  8. 8.767 + 195 =
  9. 9.835 − 382 =
  10. 10.316 + 301 =
  11. 11.679 + 119 =
  12. 12.504 − 141 =
  13. 13.371 + 406 =
  14. 14.410 + 161 =
  15. 15.978 − 237 =
  16. 16.639 − 364 =
  17. 17.455 + 161 =
  18. 18.334 + 118 =
  19. 19.539 + 512 =
  20. 20.478 + 277 =
  21. 21.506 + 617 =
  22. 22.227 + 641 =
  23. 23.405 + 191 =
  24. 24.527 + 351 =
  25. 25.792 − 211 =
  26. 26.156 + 446 =
  27. 27.255 + 136 =
  28. 28.700 − 171 =
  29. 29.489 − 144 =
  30. 30.788 + 192 =
  31. 31.989 − 183 =
  32. 32.824 − 149 =
  33. 33.870 − 633 =
  34. 34.676 + 308 =
  35. 35.584 − 274 =
  36. 36.176 + 141 =
  37. 37.440 − 259 =
  38. 38.822 − 415 =
  39. 39.526 + 625 =
  40. 40.946 − 634 =

Answer key

  1. 123
  2. 272
  3. 517
  4. 608
  5. 340
  6. 344
  7. 139
  8. 962
  9. 453
  10. 617
  11. 798
  12. 363
  13. 777
  14. 571
  15. 741
  16. 275
  17. 616
  18. 452
  19. 1051
  20. 755
  21. 1123
  22. 868
  23. 596
  24. 878
  25. 581
  26. 602
  27. 391
  28. 529
  29. 345
  30. 980
  31. 806
  32. 675
  33. 237
  34. 984
  35. 310
  36. 317
  37. 181
  38. 407
  39. 1151
  40. 312

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