← 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 663 · 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. 1.142 + 597 =
  2. 2.599 − 183 =
  3. 3.739 + 258 =
  4. 4.657 + 168 =
  5. 5.363 + 252 =
  6. 6.848 − 591 =
  7. 7.533 + 667 =
  8. 8.594 + 234 =
  9. 9.811 − 364 =
  10. 10.831 − 644 =
  11. 11.341 + 407 =
  12. 12.309 + 578 =
  13. 13.985 − 747 =
  14. 14.576 + 474 =
  15. 15.916 − 637 =
  16. 16.637 + 186 =
  17. 17.796 − 321 =
  18. 18.556 + 644 =
  19. 19.548 − 339 =
  20. 20.680 + 362 =
  21. 21.623 − 241 =
  22. 22.580 − 456 =
  23. 23.708 + 173 =
  24. 24.674 − 481 =
  25. 25.270 + 605 =
  26. 26.659 + 547 =
  27. 27.191 + 151 =
  28. 28.539 − 175 =
  29. 29.421 − 282 =
  30. 30.800 − 652 =
  31. 31.451 − 326 =
  32. 32.417 − 231 =
  33. 33.606 − 141 =
  34. 34.872 − 258 =
  35. 35.762 + 401 =
  36. 36.466 − 365 =
  37. 37.564 − 327 =
  38. 38.968 − 215 =
  39. 39.886 − 642 =
  40. 40.925 − 638 =

Answer key

  1. 739
  2. 416
  3. 997
  4. 825
  5. 615
  6. 257
  7. 1200
  8. 828
  9. 447
  10. 187
  11. 748
  12. 887
  13. 238
  14. 1050
  15. 279
  16. 823
  17. 475
  18. 1200
  19. 209
  20. 1042
  21. 382
  22. 124
  23. 881
  24. 193
  25. 875
  26. 1206
  27. 342
  28. 364
  29. 139
  30. 148
  31. 125
  32. 186
  33. 465
  34. 614
  35. 1163
  36. 101
  37. 237
  38. 753
  39. 244
  40. 287

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