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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 973 · 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. 1.699 − 187 =
  2. 2.930 − 356 =
  3. 3.447 − 171 =
  4. 4.357 + 527 =
  5. 5.967 − 711 =
  6. 6.223 + 501 =
  7. 7.850 − 697 =
  8. 8.598 − 321 =
  9. 9.265 + 657 =
  10. 10.502 − 244 =
  11. 11.820 − 385 =
  12. 12.262 + 331 =
  13. 13.744 + 512 =
  14. 14.477 − 239 =
  15. 15.230 + 591 =
  16. 16.504 + 536 =
  17. 17.725 − 118 =
  18. 18.528 + 483 =
  19. 19.518 − 183 =
  20. 20.565 − 347 =
  21. 21.477 − 331 =
  22. 22.810 − 534 =
  23. 23.748 + 645 =
  24. 24.595 − 283 =
  25. 25.165 + 287 =
  26. 26.356 + 161 =
  27. 27.970 − 149 =
  28. 28.799 − 563 =
  29. 29.796 − 449 =
  30. 30.703 + 547 =
  31. 31.478 − 167 =
  32. 32.526 − 235 =
  33. 33.835 − 369 =
  34. 34.732 − 424 =
  35. 35.907 − 637 =
  36. 36.132 + 491 =
  37. 37.679 − 243 =
  38. 38.416 − 171 =
  39. 39.479 − 118 =
  40. 40.296 + 199 =

Answer key

  1. 512
  2. 574
  3. 276
  4. 884
  5. 256
  6. 724
  7. 153
  8. 277
  9. 922
  10. 258
  11. 435
  12. 593
  13. 1256
  14. 238
  15. 821
  16. 1040
  17. 607
  18. 1011
  19. 335
  20. 218
  21. 146
  22. 276
  23. 1393
  24. 312
  25. 452
  26. 517
  27. 821
  28. 236
  29. 347
  30. 1250
  31. 311
  32. 291
  33. 466
  34. 308
  35. 270
  36. 623
  37. 436
  38. 245
  39. 361
  40. 495

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