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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 261 · 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. 1.163 + 494 =
  2. 2.751 − 131 =
  3. 3.643 − 214 =
  4. 4.406 + 196 =
  5. 5.616 + 272 =
  6. 6.633 − 429 =
  7. 7.590 − 381 =
  8. 8.763 + 386 =
  9. 9.733 − 408 =
  10. 10.733 − 625 =
  11. 11.443 − 256 =
  12. 12.163 + 546 =
  13. 13.551 + 661 =
  14. 14.606 − 117 =
  15. 15.443 + 534 =
  16. 16.712 + 119 =
  17. 17.654 + 161 =
  18. 18.529 + 497 =
  19. 19.327 + 407 =
  20. 20.278 + 155 =
  21. 21.181 + 177 =
  22. 22.364 + 182 =
  23. 23.315 + 589 =
  24. 24.349 + 182 =
  25. 25.974 − 867 =
  26. 26.294 + 558 =
  27. 27.723 − 485 =
  28. 28.207 + 226 =
  29. 29.142 + 261 =
  30. 30.476 − 151 =
  31. 31.358 + 339 =
  32. 32.255 + 274 =
  33. 33.898 − 541 =
  34. 34.870 − 686 =
  35. 35.564 + 144 =
  36. 36.648 − 321 =
  37. 37.733 − 132 =
  38. 38.580 − 211 =
  39. 39.204 + 467 =
  40. 40.954 − 123 =

Answer key

  1. 657
  2. 620
  3. 429
  4. 602
  5. 888
  6. 204
  7. 209
  8. 1149
  9. 325
  10. 108
  11. 187
  12. 709
  13. 1212
  14. 489
  15. 977
  16. 831
  17. 815
  18. 1026
  19. 734
  20. 433
  21. 358
  22. 546
  23. 904
  24. 531
  25. 107
  26. 852
  27. 238
  28. 433
  29. 403
  30. 325
  31. 697
  32. 529
  33. 357
  34. 184
  35. 708
  36. 327
  37. 601
  38. 369
  39. 671
  40. 831

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