← 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 139 · 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. 1.476 − 193 =
  2. 2.363 + 203 =
  3. 3.772 − 635 =
  4. 4.754 + 372 =
  5. 5.542 + 525 =
  6. 6.576 + 541 =
  7. 7.710 − 249 =
  8. 8.653 + 413 =
  9. 9.719 + 219 =
  10. 10.761 − 345 =
  11. 11.189 + 147 =
  12. 12.583 − 432 =
  13. 13.720 + 578 =
  14. 14.782 + 341 =
  15. 15.954 − 458 =
  16. 16.311 + 281 =
  17. 17.972 − 631 =
  18. 18.730 + 256 =
  19. 19.163 + 314 =
  20. 20.674 − 517 =
  21. 21.289 + 362 =
  22. 22.872 − 212 =
  23. 23.514 + 516 =
  24. 24.182 + 441 =
  25. 25.553 − 388 =
  26. 26.386 + 307 =
  27. 27.906 − 584 =
  28. 28.547 − 351 =
  29. 29.798 − 508 =
  30. 30.373 + 345 =
  31. 31.692 − 466 =
  32. 32.469 − 176 =
  33. 33.462 + 621 =
  34. 34.728 + 541 =
  35. 35.499 + 423 =
  36. 36.698 + 193 =
  37. 37.377 + 241 =
  38. 38.496 − 234 =
  39. 39.301 + 477 =
  40. 40.620 − 226 =

Answer key

  1. 283
  2. 566
  3. 137
  4. 1126
  5. 1067
  6. 1117
  7. 461
  8. 1066
  9. 938
  10. 416
  11. 336
  12. 151
  13. 1298
  14. 1123
  15. 496
  16. 592
  17. 341
  18. 986
  19. 477
  20. 157
  21. 651
  22. 660
  23. 1030
  24. 623
  25. 165
  26. 693
  27. 322
  28. 196
  29. 290
  30. 718
  31. 226
  32. 293
  33. 1083
  34. 1269
  35. 922
  36. 891
  37. 618
  38. 262
  39. 778
  40. 394

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