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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 920 · 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. 1.498 − 228 =
  2. 2.877 − 701 =
  3. 3.314 + 223 =
  4. 4.780 + 291 =
  5. 5.949 − 117 =
  6. 6.542 − 131 =
  7. 7.396 + 149 =
  8. 8.905 − 791 =
  9. 9.254 + 573 =
  10. 10.559 − 371 =
  11. 11.777 − 232 =
  12. 12.631 + 627 =
  13. 13.718 + 307 =
  14. 14.501 − 192 =
  15. 15.817 − 469 =
  16. 16.248 + 343 =
  17. 17.714 − 116 =
  18. 18.532 + 463 =
  19. 19.340 + 522 =
  20. 20.865 − 329 =
  21. 21.370 + 232 =
  22. 22.497 + 591 =
  23. 23.931 − 287 =
  24. 24.757 + 415 =
  25. 25.946 − 404 =
  26. 26.434 − 286 =
  27. 27.443 + 511 =
  28. 28.498 + 239 =
  29. 29.354 + 298 =
  30. 30.268 + 152 =
  31. 31.477 − 239 =
  32. 32.608 + 269 =
  33. 33.428 + 189 =
  34. 34.231 + 635 =
  35. 35.874 − 676 =
  36. 36.655 + 186 =
  37. 37.527 − 185 =
  38. 38.287 + 465 =
  39. 39.745 − 545 =
  40. 40.437 + 197 =

Answer key

  1. 270
  2. 176
  3. 537
  4. 1071
  5. 832
  6. 411
  7. 545
  8. 114
  9. 827
  10. 188
  11. 545
  12. 1258
  13. 1025
  14. 309
  15. 348
  16. 591
  17. 598
  18. 995
  19. 862
  20. 536
  21. 602
  22. 1088
  23. 644
  24. 1172
  25. 542
  26. 148
  27. 954
  28. 737
  29. 652
  30. 420
  31. 238
  32. 877
  33. 617
  34. 866
  35. 198
  36. 841
  37. 342
  38. 752
  39. 200
  40. 634

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