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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 882 · 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. 1.183 + 541 =
  2. 2.679 − 266 =
  3. 3.433 − 229 =
  4. 4.498 + 676 =
  5. 5.216 + 411 =
  6. 6.311 + 223 =
  7. 7.558 − 186 =
  8. 8.971 − 473 =
  9. 9.923 − 661 =
  10. 10.166 + 283 =
  11. 11.607 − 221 =
  12. 12.230 + 121 =
  13. 13.859 − 568 =
  14. 14.806 − 134 =
  15. 15.200 + 601 =
  16. 16.538 − 348 =
  17. 17.748 + 498 =
  18. 18.389 + 657 =
  19. 19.478 + 206 =
  20. 20.851 − 449 =
  21. 21.921 − 655 =
  22. 22.772 + 645 =
  23. 23.209 + 599 =
  24. 24.673 + 286 =
  25. 25.740 − 503 =
  26. 26.471 − 296 =
  27. 27.325 + 517 =
  28. 28.627 − 239 =
  29. 29.530 + 151 =
  30. 30.699 + 244 =
  31. 31.337 + 375 =
  32. 32.322 + 273 =
  33. 33.407 + 363 =
  34. 34.191 + 452 =
  35. 35.696 − 285 =
  36. 36.127 + 485 =
  37. 37.473 − 211 =
  38. 38.698 − 473 =
  39. 39.440 − 301 =
  40. 40.747 + 149 =

Answer key

  1. 724
  2. 413
  3. 204
  4. 1174
  5. 627
  6. 534
  7. 372
  8. 498
  9. 262
  10. 449
  11. 386
  12. 351
  13. 291
  14. 672
  15. 801
  16. 190
  17. 1246
  18. 1046
  19. 684
  20. 402
  21. 266
  22. 1417
  23. 808
  24. 959
  25. 237
  26. 175
  27. 842
  28. 388
  29. 681
  30. 943
  31. 712
  32. 595
  33. 770
  34. 643
  35. 411
  36. 612
  37. 262
  38. 225
  39. 139
  40. 896

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