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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 522 · 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. 1.457 − 223 =
  2. 2.505 − 247 =
  3. 3.722 − 396 =
  4. 4.870 − 403 =
  5. 5.287 + 336 =
  6. 6.754 − 289 =
  7. 7.324 + 389 =
  8. 8.711 − 357 =
  9. 9.853 − 151 =
  10. 10.273 + 607 =
  11. 11.207 + 621 =
  12. 12.476 − 219 =
  13. 13.726 + 128 =
  14. 14.593 − 331 =
  15. 15.607 + 115 =
  16. 16.549 + 405 =
  17. 17.746 + 125 =
  18. 18.221 + 607 =
  19. 19.475 − 232 =
  20. 20.832 − 689 =
  21. 21.675 − 525 =
  22. 22.698 − 524 =
  23. 23.414 + 624 =
  24. 24.547 − 434 =
  25. 25.659 − 157 =
  26. 26.764 + 178 =
  27. 27.734 − 541 =
  28. 28.204 + 289 =
  29. 29.322 + 341 =
  30. 30.327 + 576 =
  31. 31.793 − 384 =
  32. 32.512 + 599 =
  33. 33.648 − 157 =
  34. 34.581 − 131 =
  35. 35.981 − 132 =
  36. 36.570 − 255 =
  37. 37.564 + 534 =
  38. 38.534 + 538 =
  39. 39.710 − 553 =
  40. 40.434 − 291 =

Answer key

  1. 234
  2. 258
  3. 326
  4. 467
  5. 623
  6. 465
  7. 713
  8. 354
  9. 702
  10. 880
  11. 828
  12. 257
  13. 854
  14. 262
  15. 722
  16. 954
  17. 871
  18. 828
  19. 243
  20. 143
  21. 150
  22. 174
  23. 1038
  24. 113
  25. 502
  26. 942
  27. 193
  28. 493
  29. 663
  30. 903
  31. 409
  32. 1111
  33. 491
  34. 450
  35. 849
  36. 315
  37. 1098
  38. 1072
  39. 157
  40. 143

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