← 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 192 · 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. 1.651 + 504 =
  2. 2.708 + 329 =
  3. 3.870 − 184 =
  4. 4.730 − 144 =
  5. 5.563 − 444 =
  6. 6.822 − 711 =
  7. 7.522 + 589 =
  8. 8.283 + 606 =
  9. 9.964 − 653 =
  10. 10.373 + 227 =
  11. 11.282 + 181 =
  12. 12.348 + 669 =
  13. 13.640 + 414 =
  14. 14.782 + 647 =
  15. 15.375 + 405 =
  16. 16.167 + 521 =
  17. 17.555 + 122 =
  18. 18.594 + 346 =
  19. 19.684 + 144 =
  20. 20.535 + 428 =
  21. 21.515 − 179 =
  22. 22.256 + 424 =
  23. 23.182 + 331 =
  24. 24.885 − 575 =
  25. 25.601 + 648 =
  26. 26.710 − 393 =
  27. 27.209 + 672 =
  28. 28.219 + 193 =
  29. 29.505 + 114 =
  30. 30.956 − 641 =
  31. 31.516 + 122 =
  32. 32.251 + 332 =
  33. 33.423 − 314 =
  34. 34.821 − 281 =
  35. 35.622 + 246 =
  36. 36.590 + 404 =
  37. 37.811 − 234 =
  38. 38.342 + 142 =
  39. 39.136 + 162 =
  40. 40.892 − 443 =

Answer key

  1. 1155
  2. 1037
  3. 686
  4. 586
  5. 119
  6. 111
  7. 1111
  8. 889
  9. 311
  10. 600
  11. 463
  12. 1017
  13. 1054
  14. 1429
  15. 780
  16. 688
  17. 677
  18. 940
  19. 828
  20. 963
  21. 336
  22. 680
  23. 513
  24. 310
  25. 1249
  26. 317
  27. 881
  28. 412
  29. 619
  30. 315
  31. 638
  32. 583
  33. 109
  34. 540
  35. 868
  36. 994
  37. 577
  38. 484
  39. 298
  40. 449

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