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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 169 · 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. 1.808 − 247 =
  2. 2.294 + 536 =
  3. 3.250 + 458 =
  4. 4.730 + 414 =
  5. 5.417 + 408 =
  6. 6.330 + 588 =
  7. 7.844 − 394 =
  8. 8.913 − 121 =
  9. 9.221 + 475 =
  10. 10.624 + 412 =
  11. 11.474 + 515 =
  12. 12.910 − 231 =
  13. 13.688 − 121 =
  14. 14.938 − 278 =
  15. 15.721 + 389 =
  16. 16.985 − 191 =
  17. 17.693 − 212 =
  18. 18.247 + 317 =
  19. 19.803 − 441 =
  20. 20.491 − 219 =
  21. 21.524 − 412 =
  22. 22.912 − 775 =
  23. 23.946 − 679 =
  24. 24.581 + 561 =
  25. 25.692 + 127 =
  26. 26.418 − 288 =
  27. 27.686 − 132 =
  28. 28.683 + 263 =
  29. 29.664 − 191 =
  30. 30.137 + 117 =
  31. 31.754 − 433 =
  32. 32.133 + 151 =
  33. 33.450 − 161 =
  34. 34.185 + 551 =
  35. 35.577 − 222 =
  36. 36.827 − 682 =
  37. 37.161 + 172 =
  38. 38.539 − 417 =
  39. 39.508 + 487 =
  40. 40.211 + 353 =

Answer key

  1. 561
  2. 830
  3. 708
  4. 1144
  5. 825
  6. 918
  7. 450
  8. 792
  9. 696
  10. 1036
  11. 989
  12. 679
  13. 567
  14. 660
  15. 1110
  16. 794
  17. 481
  18. 564
  19. 362
  20. 272
  21. 112
  22. 137
  23. 267
  24. 1142
  25. 819
  26. 130
  27. 554
  28. 946
  29. 473
  30. 254
  31. 321
  32. 284
  33. 289
  34. 736
  35. 355
  36. 145
  37. 333
  38. 122
  39. 995
  40. 564

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