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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 673 · 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. 1.761 − 349 =
  2. 2.436 + 222 =
  3. 3.446 + 593 =
  4. 4.810 − 392 =
  5. 5.230 + 636 =
  6. 6.744 − 574 =
  7. 7.190 + 582 =
  8. 8.545 + 487 =
  9. 9.423 + 172 =
  10. 10.165 + 386 =
  11. 11.512 + 503 =
  12. 12.448 − 201 =
  13. 13.989 − 341 =
  14. 14.352 + 575 =
  15. 15.917 − 649 =
  16. 16.853 − 411 =
  17. 17.759 + 195 =
  18. 18.483 − 292 =
  19. 19.654 − 461 =
  20. 20.813 − 543 =
  21. 21.854 − 431 =
  22. 22.851 − 408 =
  23. 23.572 − 261 =
  24. 24.820 − 711 =
  25. 25.593 + 185 =
  26. 26.737 + 624 =
  27. 27.737 − 189 =
  28. 28.757 + 309 =
  29. 29.558 + 572 =
  30. 30.226 + 488 =
  31. 31.528 + 385 =
  32. 32.752 + 515 =
  33. 33.305 + 136 =
  34. 34.645 − 196 =
  35. 35.519 + 588 =
  36. 36.617 − 488 =
  37. 37.545 + 269 =
  38. 38.398 + 248 =
  39. 39.411 + 667 =
  40. 40.872 − 382 =

Answer key

  1. 412
  2. 658
  3. 1039
  4. 418
  5. 866
  6. 170
  7. 772
  8. 1032
  9. 595
  10. 551
  11. 1015
  12. 247
  13. 648
  14. 927
  15. 268
  16. 442
  17. 954
  18. 191
  19. 193
  20. 270
  21. 423
  22. 443
  23. 311
  24. 109
  25. 778
  26. 1361
  27. 548
  28. 1066
  29. 1130
  30. 714
  31. 913
  32. 1267
  33. 441
  34. 449
  35. 1107
  36. 129
  37. 814
  38. 646
  39. 1078
  40. 490

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