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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 320 · 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. 1.693 − 571 =
  2. 2.412 + 259 =
  3. 3.433 − 207 =
  4. 4.678 − 458 =
  5. 5.734 + 485 =
  6. 6.542 − 225 =
  7. 7.443 − 243 =
  8. 8.802 − 691 =
  9. 9.354 + 415 =
  10. 10.402 + 317 =
  11. 11.503 − 238 =
  12. 12.837 − 704 =
  13. 13.292 + 168 =
  14. 14.505 + 523 =
  15. 15.893 − 412 =
  16. 16.922 − 231 =
  17. 17.630 + 268 =
  18. 18.193 + 371 =
  19. 19.484 − 298 =
  20. 20.655 + 576 =
  21. 21.869 − 502 =
  22. 22.467 + 501 =
  23. 23.279 + 214 =
  24. 24.489 − 133 =
  25. 25.588 − 316 =
  26. 26.852 − 384 =
  27. 27.590 + 348 =
  28. 28.786 − 303 =
  29. 29.871 − 284 =
  30. 30.343 + 528 =
  31. 31.590 + 503 =
  32. 32.788 + 392 =
  33. 33.529 − 336 =
  34. 34.902 − 312 =
  35. 35.496 + 464 =
  36. 36.838 − 613 =
  37. 37.573 − 287 =
  38. 38.433 − 116 =
  39. 39.162 + 531 =
  40. 40.295 + 401 =

Answer key

  1. 122
  2. 671
  3. 226
  4. 220
  5. 1219
  6. 317
  7. 200
  8. 111
  9. 769
  10. 719
  11. 265
  12. 133
  13. 460
  14. 1028
  15. 481
  16. 691
  17. 898
  18. 564
  19. 186
  20. 1231
  21. 367
  22. 968
  23. 493
  24. 356
  25. 272
  26. 468
  27. 938
  28. 483
  29. 587
  30. 871
  31. 1093
  32. 1180
  33. 193
  34. 590
  35. 960
  36. 225
  37. 286
  38. 317
  39. 693
  40. 696

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