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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 884 · 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. 1.759 − 197 =
  2. 2.777 − 136 =
  3. 3.633 − 394 =
  4. 4.649 − 221 =
  5. 5.279 + 562 =
  6. 6.741 − 233 =
  7. 7.639 − 532 =
  8. 8.160 + 338 =
  9. 9.413 + 162 =
  10. 10.736 + 201 =
  11. 11.478 + 261 =
  12. 12.535 + 329 =
  13. 13.917 − 665 =
  14. 14.828 − 342 =
  15. 15.281 + 311 =
  16. 16.492 + 213 =
  17. 17.916 − 471 =
  18. 18.271 + 546 =
  19. 19.557 − 181 =
  20. 20.241 + 663 =
  21. 21.265 + 457 =
  22. 22.143 + 451 =
  23. 23.517 − 354 =
  24. 24.741 + 195 =
  25. 25.696 − 131 =
  26. 26.865 − 158 =
  27. 27.515 − 336 =
  28. 28.205 + 621 =
  29. 29.319 + 237 =
  30. 30.439 + 641 =
  31. 31.586 − 468 =
  32. 32.596 + 423 =
  33. 33.617 − 312 =
  34. 34.693 − 375 =
  35. 35.551 − 347 =
  36. 36.820 − 151 =
  37. 37.465 − 177 =
  38. 38.389 + 255 =
  39. 39.184 + 457 =
  40. 40.273 + 155 =

Answer key

  1. 562
  2. 641
  3. 239
  4. 428
  5. 841
  6. 508
  7. 107
  8. 498
  9. 575
  10. 937
  11. 739
  12. 864
  13. 252
  14. 486
  15. 592
  16. 705
  17. 445
  18. 817
  19. 376
  20. 904
  21. 722
  22. 594
  23. 163
  24. 936
  25. 565
  26. 707
  27. 179
  28. 826
  29. 556
  30. 1080
  31. 118
  32. 1019
  33. 305
  34. 318
  35. 204
  36. 669
  37. 288
  38. 644
  39. 641
  40. 428

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