← 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 949 · 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. 1.491 − 281 =
  2. 2.868 − 511 =
  3. 3.690 − 382 =
  4. 4.521 + 322 =
  5. 5.642 + 113 =
  6. 6.680 + 211 =
  7. 7.700 − 146 =
  8. 8.440 + 133 =
  9. 9.739 − 608 =
  10. 10.569 + 441 =
  11. 11.178 + 374 =
  12. 12.689 + 628 =
  13. 13.537 − 134 =
  14. 14.540 + 685 =
  15. 15.537 + 485 =
  16. 16.974 − 343 =
  17. 17.531 − 417 =
  18. 18.176 + 679 =
  19. 19.557 − 201 =
  20. 20.563 − 243 =
  21. 21.612 + 123 =
  22. 22.595 − 335 =
  23. 23.756 + 187 =
  24. 24.814 − 642 =
  25. 25.500 − 147 =
  26. 26.532 − 331 =
  27. 27.450 − 345 =
  28. 28.604 − 174 =
  29. 29.696 − 515 =
  30. 30.651 + 261 =
  31. 31.261 + 661 =
  32. 32.694 − 391 =
  33. 33.771 − 499 =
  34. 34.433 + 297 =
  35. 35.181 + 272 =
  36. 36.638 + 147 =
  37. 37.543 − 333 =
  38. 38.563 − 122 =
  39. 39.746 + 177 =
  40. 40.680 + 609 =

Answer key

  1. 210
  2. 357
  3. 308
  4. 843
  5. 755
  6. 891
  7. 554
  8. 573
  9. 131
  10. 1010
  11. 552
  12. 1317
  13. 403
  14. 1225
  15. 1022
  16. 631
  17. 114
  18. 855
  19. 356
  20. 320
  21. 735
  22. 260
  23. 943
  24. 172
  25. 353
  26. 201
  27. 105
  28. 430
  29. 181
  30. 912
  31. 922
  32. 303
  33. 272
  34. 730
  35. 453
  36. 785
  37. 210
  38. 441
  39. 923
  40. 1289

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