← 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 825 · 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. 1.756 − 161 =
  2. 2.966 − 668 =
  3. 3.559 + 284 =
  4. 4.583 + 116 =
  5. 5.521 + 588 =
  6. 6.973 − 646 =
  7. 7.312 + 601 =
  8. 8.583 − 443 =
  9. 9.532 − 188 =
  10. 10.294 + 547 =
  11. 11.500 − 172 =
  12. 12.988 − 295 =
  13. 13.464 + 322 =
  14. 14.301 + 386 =
  15. 15.792 − 138 =
  16. 16.411 + 406 =
  17. 17.880 − 433 =
  18. 18.746 − 186 =
  19. 19.380 + 416 =
  20. 20.534 + 226 =
  21. 21.432 + 133 =
  22. 22.928 − 407 =
  23. 23.215 + 132 =
  24. 24.420 − 229 =
  25. 25.528 + 656 =
  26. 26.463 + 591 =
  27. 27.363 + 269 =
  28. 28.474 + 361 =
  29. 29.271 + 218 =
  30. 30.744 + 551 =
  31. 31.855 − 424 =
  32. 32.756 + 417 =
  33. 33.559 + 263 =
  34. 34.613 + 261 =
  35. 35.153 + 408 =
  36. 36.497 − 349 =
  37. 37.546 − 241 =
  38. 38.498 + 559 =
  39. 39.677 + 181 =
  40. 40.500 − 305 =

Answer key

  1. 595
  2. 298
  3. 843
  4. 699
  5. 1109
  6. 327
  7. 913
  8. 140
  9. 344
  10. 841
  11. 328
  12. 693
  13. 786
  14. 687
  15. 654
  16. 817
  17. 447
  18. 560
  19. 796
  20. 760
  21. 565
  22. 521
  23. 347
  24. 191
  25. 1184
  26. 1054
  27. 632
  28. 835
  29. 489
  30. 1295
  31. 431
  32. 1173
  33. 822
  34. 874
  35. 561
  36. 148
  37. 305
  38. 1057
  39. 858
  40. 195

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