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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 838 · 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. 1.492 − 259 =
  2. 2.418 − 239 =
  3. 3.451 − 241 =
  4. 4.430 − 161 =
  5. 5.901 − 414 =
  6. 6.478 + 616 =
  7. 7.435 − 274 =
  8. 8.522 − 363 =
  9. 9.832 − 728 =
  10. 10.604 − 204 =
  11. 11.440 − 113 =
  12. 12.848 − 156 =
  13. 13.206 + 228 =
  14. 14.150 + 363 =
  15. 15.873 − 615 =
  16. 16.443 − 303 =
  17. 17.627 − 356 =
  18. 18.706 + 273 =
  19. 19.366 + 279 =
  20. 20.343 + 194 =
  21. 21.630 − 136 =
  22. 22.963 − 665 =
  23. 23.151 + 279 =
  24. 24.411 + 506 =
  25. 25.647 + 566 =
  26. 26.561 + 134 =
  27. 27.225 + 355 =
  28. 28.721 − 277 =
  29. 29.301 + 149 =
  30. 30.447 − 346 =
  31. 31.239 + 181 =
  32. 32.482 + 381 =
  33. 33.650 − 498 =
  34. 34.970 − 131 =
  35. 35.882 − 575 =
  36. 36.622 + 524 =
  37. 37.574 − 383 =
  38. 38.277 + 616 =
  39. 39.504 + 338 =
  40. 40.573 − 172 =

Answer key

  1. 233
  2. 179
  3. 210
  4. 269
  5. 487
  6. 1094
  7. 161
  8. 159
  9. 104
  10. 400
  11. 327
  12. 692
  13. 434
  14. 513
  15. 258
  16. 140
  17. 271
  18. 979
  19. 645
  20. 537
  21. 494
  22. 298
  23. 430
  24. 917
  25. 1213
  26. 695
  27. 580
  28. 444
  29. 450
  30. 101
  31. 420
  32. 863
  33. 152
  34. 839
  35. 307
  36. 1146
  37. 191
  38. 893
  39. 842
  40. 401

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