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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 220 · 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. 1.624 + 203 =
  2. 2.251 + 261 =
  3. 3.509 + 644 =
  4. 4.852 − 181 =
  5. 5.729 − 541 =
  6. 6.786 − 467 =
  7. 7.761 + 684 =
  8. 8.266 + 353 =
  9. 9.424 − 273 =
  10. 10.338 + 367 =
  11. 11.222 + 508 =
  12. 12.699 + 281 =
  13. 13.966 − 441 =
  14. 14.981 − 395 =
  15. 15.297 + 136 =
  16. 16.490 − 179 =
  17. 17.181 + 564 =
  18. 18.949 − 466 =
  19. 19.555 − 113 =
  20. 20.617 − 313 =
  21. 21.272 + 138 =
  22. 22.505 + 545 =
  23. 23.579 + 493 =
  24. 24.599 + 469 =
  25. 25.706 − 293 =
  26. 26.329 + 267 =
  27. 27.649 + 542 =
  28. 28.164 + 501 =
  29. 29.494 + 513 =
  30. 30.908 − 792 =
  31. 31.160 + 236 =
  32. 32.681 + 462 =
  33. 33.251 + 419 =
  34. 34.785 − 202 =
  35. 35.989 − 114 =
  36. 36.416 + 412 =
  37. 37.431 − 213 =
  38. 38.326 + 395 =
  39. 39.180 + 502 =
  40. 40.989 − 496 =

Answer key

  1. 827
  2. 512
  3. 1153
  4. 671
  5. 188
  6. 319
  7. 1445
  8. 619
  9. 151
  10. 705
  11. 730
  12. 980
  13. 525
  14. 586
  15. 433
  16. 311
  17. 745
  18. 483
  19. 442
  20. 304
  21. 410
  22. 1050
  23. 1072
  24. 1068
  25. 413
  26. 596
  27. 1191
  28. 665
  29. 1007
  30. 116
  31. 396
  32. 1143
  33. 670
  34. 583
  35. 875
  36. 828
  37. 218
  38. 721
  39. 682
  40. 493

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