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3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 746 · 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. 1.288 + 265 =
  2. 2.880 − 352 =
  3. 3.612 − 421 =
  4. 4.718 − 387 =
  5. 5.458 − 307 =
  6. 6.149 + 122 =
  7. 7.300 + 589 =
  8. 8.469 + 287 =
  9. 9.733 + 361 =
  10. 10.580 + 471 =
  11. 11.674 − 243 =
  12. 12.910 − 721 =
  13. 13.664 + 675 =
  14. 14.719 + 192 =
  15. 15.968 − 832 =
  16. 16.566 − 133 =
  17. 17.615 + 405 =
  18. 18.421 − 266 =
  19. 19.568 + 251 =
  20. 20.777 − 406 =
  21. 21.816 − 298 =
  22. 22.237 + 294 =
  23. 23.638 + 236 =
  24. 24.502 − 233 =
  25. 25.683 + 424 =
  26. 26.559 − 231 =
  27. 27.824 − 542 =
  28. 28.596 − 356 =
  29. 29.229 + 215 =
  30. 30.714 + 211 =
  31. 31.803 − 445 =
  32. 32.798 − 346 =
  33. 33.326 + 483 =
  34. 34.934 − 803 =
  35. 35.836 − 384 =
  36. 36.929 − 704 =
  37. 37.561 − 446 =
  38. 38.574 − 225 =
  39. 39.731 + 556 =
  40. 40.603 − 183 =

Answer key

  1. 553
  2. 528
  3. 191
  4. 331
  5. 151
  6. 271
  7. 889
  8. 756
  9. 1094
  10. 1051
  11. 431
  12. 189
  13. 1339
  14. 911
  15. 136
  16. 433
  17. 1020
  18. 155
  19. 819
  20. 371
  21. 518
  22. 531
  23. 874
  24. 269
  25. 1107
  26. 328
  27. 282
  28. 240
  29. 444
  30. 925
  31. 358
  32. 452
  33. 809
  34. 131
  35. 452
  36. 225
  37. 115
  38. 349
  39. 1287
  40. 420

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