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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 594 · 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. 1.768 − 385 =
  2. 2.460 − 124 =
  3. 3.619 − 308 =
  4. 4.316 + 634 =
  5. 5.678 + 451 =
  6. 6.915 − 245 =
  7. 7.481 + 223 =
  8. 8.453 − 164 =
  9. 9.422 + 174 =
  10. 10.976 − 446 =
  11. 11.659 + 185 =
  12. 12.569 + 206 =
  13. 13.437 + 284 =
  14. 14.785 − 547 =
  15. 15.602 + 551 =
  16. 16.757 + 527 =
  17. 17.756 − 265 =
  18. 18.565 + 263 =
  19. 19.434 + 284 =
  20. 20.986 − 304 =
  21. 21.660 + 669 =
  22. 22.272 + 587 =
  23. 23.643 − 332 =
  24. 24.711 + 523 =
  25. 25.852 − 145 =
  26. 26.456 − 141 =
  27. 27.136 + 115 =
  28. 28.171 + 467 =
  29. 29.278 + 155 =
  30. 30.875 − 167 =
  31. 31.743 + 569 =
  32. 32.784 − 399 =
  33. 33.777 − 384 =
  34. 34.497 − 192 =
  35. 35.329 + 402 =
  36. 36.533 − 194 =
  37. 37.322 + 159 =
  38. 38.468 − 195 =
  39. 39.564 + 323 =
  40. 40.419 + 602 =

Answer key

  1. 383
  2. 336
  3. 311
  4. 950
  5. 1129
  6. 670
  7. 704
  8. 289
  9. 596
  10. 530
  11. 844
  12. 775
  13. 721
  14. 238
  15. 1153
  16. 1284
  17. 491
  18. 828
  19. 718
  20. 682
  21. 1329
  22. 859
  23. 311
  24. 1234
  25. 707
  26. 315
  27. 251
  28. 638
  29. 433
  30. 708
  31. 1312
  32. 385
  33. 393
  34. 305
  35. 731
  36. 339
  37. 481
  38. 273
  39. 887
  40. 1021

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