← 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 782 · 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. 1.353 + 552 =
  2. 2.785 − 592 =
  3. 3.703 − 497 =
  4. 4.215 + 453 =
  5. 5.256 + 129 =
  6. 6.373 + 546 =
  7. 7.718 − 147 =
  8. 8.581 − 118 =
  9. 9.659 − 273 =
  10. 10.702 − 172 =
  11. 11.759 + 133 =
  12. 12.435 − 151 =
  13. 13.932 − 774 =
  14. 14.372 + 171 =
  15. 15.487 + 571 =
  16. 16.813 − 431 =
  17. 17.694 − 352 =
  18. 18.595 − 115 =
  19. 19.463 − 261 =
  20. 20.160 + 592 =
  21. 21.847 − 707 =
  22. 22.344 + 238 =
  23. 23.729 − 159 =
  24. 24.510 + 396 =
  25. 25.508 + 528 =
  26. 26.191 + 598 =
  27. 27.612 + 222 =
  28. 28.324 + 265 =
  29. 29.492 + 195 =
  30. 30.678 + 211 =
  31. 31.554 + 146 =
  32. 32.742 − 449 =
  33. 33.588 + 643 =
  34. 34.711 − 606 =
  35. 35.440 − 207 =
  36. 36.782 − 151 =
  37. 37.811 − 599 =
  38. 38.147 + 141 =
  39. 39.450 − 225 =
  40. 40.349 + 119 =

Answer key

  1. 905
  2. 193
  3. 206
  4. 668
  5. 385
  6. 919
  7. 571
  8. 463
  9. 386
  10. 530
  11. 892
  12. 284
  13. 158
  14. 543
  15. 1058
  16. 382
  17. 342
  18. 480
  19. 202
  20. 752
  21. 140
  22. 582
  23. 570
  24. 906
  25. 1036
  26. 789
  27. 834
  28. 589
  29. 687
  30. 889
  31. 700
  32. 293
  33. 1231
  34. 105
  35. 233
  36. 631
  37. 212
  38. 288
  39. 225
  40. 468

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