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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 57 · 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. 1.525 − 184 =
  2. 2.602 − 395 =
  3. 3.724 + 454 =
  4. 4.679 − 202 =
  5. 5.424 − 148 =
  6. 6.507 + 145 =
  7. 7.204 + 256 =
  8. 8.934 − 648 =
  9. 9.709 − 349 =
  10. 10.156 + 441 =
  11. 11.697 + 177 =
  12. 12.362 + 619 =
  13. 13.850 − 259 =
  14. 14.652 + 377 =
  15. 15.345 + 285 =
  16. 16.856 − 687 =
  17. 17.869 − 314 =
  18. 18.757 + 211 =
  19. 19.343 + 186 =
  20. 20.203 + 125 =
  21. 21.421 − 304 =
  22. 22.811 − 282 =
  23. 23.624 − 459 =
  24. 24.267 + 626 =
  25. 25.735 − 321 =
  26. 26.288 + 253 =
  27. 27.197 + 296 =
  28. 28.204 + 471 =
  29. 29.596 + 558 =
  30. 30.422 + 669 =
  31. 31.492 − 348 =
  32. 32.632 − 286 =
  33. 33.161 + 511 =
  34. 34.862 − 221 =
  35. 35.207 + 397 =
  36. 36.823 − 535 =
  37. 37.631 + 373 =
  38. 38.655 − 453 =
  39. 39.853 − 417 =
  40. 40.856 − 305 =

Answer key

  1. 341
  2. 207
  3. 1178
  4. 477
  5. 276
  6. 652
  7. 460
  8. 286
  9. 360
  10. 597
  11. 874
  12. 981
  13. 591
  14. 1029
  15. 630
  16. 169
  17. 555
  18. 968
  19. 529
  20. 328
  21. 117
  22. 529
  23. 165
  24. 893
  25. 414
  26. 541
  27. 493
  28. 675
  29. 1154
  30. 1091
  31. 144
  32. 346
  33. 672
  34. 641
  35. 604
  36. 288
  37. 1004
  38. 202
  39. 436
  40. 551

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