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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 528 · 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. 1.460 − 245 =
  2. 2.963 − 684 =
  3. 3.147 + 346 =
  4. 4.810 − 526 =
  5. 5.460 − 123 =
  6. 6.646 − 158 =
  7. 7.738 − 182 =
  8. 8.573 + 562 =
  9. 9.204 + 266 =
  10. 10.761 + 144 =
  11. 11.650 − 322 =
  12. 12.598 − 352 =
  13. 13.656 + 488 =
  14. 14.400 + 504 =
  15. 15.247 + 569 =
  16. 16.604 + 539 =
  17. 17.614 + 255 =
  18. 18.518 − 154 =
  19. 19.467 − 259 =
  20. 20.260 + 157 =
  21. 21.707 + 189 =
  22. 22.522 + 317 =
  23. 23.900 − 171 =
  24. 24.255 + 357 =
  25. 25.271 + 473 =
  26. 26.629 − 478 =
  27. 27.475 − 156 =
  28. 28.714 − 566 =
  29. 29.676 + 371 =
  30. 30.757 + 232 =
  31. 31.922 − 318 =
  32. 32.701 + 415 =
  33. 33.853 − 141 =
  34. 34.625 + 415 =
  35. 35.757 − 553 =
  36. 36.294 + 164 =
  37. 37.314 + 508 =
  38. 38.961 − 823 =
  39. 39.486 + 326 =
  40. 40.517 + 194 =

Answer key

  1. 215
  2. 279
  3. 493
  4. 284
  5. 337
  6. 488
  7. 556
  8. 1135
  9. 470
  10. 905
  11. 328
  12. 246
  13. 1144
  14. 904
  15. 816
  16. 1143
  17. 869
  18. 364
  19. 208
  20. 417
  21. 896
  22. 839
  23. 729
  24. 612
  25. 744
  26. 151
  27. 319
  28. 148
  29. 1047
  30. 989
  31. 604
  32. 1116
  33. 712
  34. 1040
  35. 204
  36. 458
  37. 822
  38. 138
  39. 812
  40. 711

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