← 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 648 · 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. 1.693 − 424 =
  2. 2.904 − 404 =
  3. 3.814 − 297 =
  4. 4.320 + 355 =
  5. 5.320 + 591 =
  6. 6.565 − 266 =
  7. 7.241 + 434 =
  8. 8.270 + 372 =
  9. 9.518 + 306 =
  10. 10.960 − 273 =
  11. 11.588 + 306 =
  12. 12.721 + 558 =
  13. 13.452 − 309 =
  14. 14.516 − 375 =
  15. 15.745 − 121 =
  16. 16.953 − 576 =
  17. 17.737 + 484 =
  18. 18.593 − 334 =
  19. 19.701 − 126 =
  20. 20.746 + 118 =
  21. 21.560 + 148 =
  22. 22.500 − 244 =
  23. 23.432 − 257 =
  24. 24.166 + 347 =
  25. 25.624 + 163 =
  26. 26.674 − 298 =
  27. 27.979 − 686 =
  28. 28.577 − 341 =
  29. 29.204 + 139 =
  30. 30.891 − 555 =
  31. 31.595 − 459 =
  32. 32.691 − 261 =
  33. 33.127 + 651 =
  34. 34.343 + 391 =
  35. 35.366 + 237 =
  36. 36.467 − 354 =
  37. 37.558 − 302 =
  38. 38.482 − 161 =
  39. 39.508 + 499 =
  40. 40.789 + 685 =

Answer key

  1. 269
  2. 500
  3. 517
  4. 675
  5. 911
  6. 299
  7. 675
  8. 642
  9. 824
  10. 687
  11. 894
  12. 1279
  13. 143
  14. 141
  15. 624
  16. 377
  17. 1221
  18. 259
  19. 575
  20. 864
  21. 708
  22. 256
  23. 175
  24. 513
  25. 787
  26. 376
  27. 293
  28. 236
  29. 343
  30. 336
  31. 136
  32. 430
  33. 778
  34. 734
  35. 603
  36. 113
  37. 256
  38. 321
  39. 1007
  40. 1474

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