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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 585 · 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. 1.691 − 441 =
  2. 2.593 − 258 =
  3. 3.589 − 402 =
  4. 4.134 + 566 =
  5. 5.813 − 662 =
  6. 6.444 − 323 =
  7. 7.499 + 393 =
  8. 8.534 + 317 =
  9. 9.485 − 336 =
  10. 10.456 + 133 =
  11. 11.736 − 189 =
  12. 12.367 + 443 =
  13. 13.228 + 251 =
  14. 14.695 + 462 =
  15. 15.588 + 394 =
  16. 16.495 + 117 =
  17. 17.651 + 641 =
  18. 18.478 − 307 =
  19. 19.398 + 547 =
  20. 20.475 − 219 =
  21. 21.921 − 554 =
  22. 22.533 + 371 =
  23. 23.260 + 506 =
  24. 24.673 − 516 =
  25. 25.156 + 453 =
  26. 26.192 + 374 =
  27. 27.328 + 113 =
  28. 28.389 + 201 =
  29. 29.469 + 653 =
  30. 30.933 − 263 =
  31. 31.725 + 371 =
  32. 32.176 + 172 =
  33. 33.745 − 611 =
  34. 34.584 − 143 =
  35. 35.617 − 393 =
  36. 36.487 − 281 =
  37. 37.546 + 367 =
  38. 38.560 + 192 =
  39. 39.361 + 551 =
  40. 40.708 + 266 =

Answer key

  1. 250
  2. 335
  3. 187
  4. 700
  5. 151
  6. 121
  7. 892
  8. 851
  9. 149
  10. 589
  11. 547
  12. 810
  13. 479
  14. 1157
  15. 982
  16. 612
  17. 1292
  18. 171
  19. 945
  20. 256
  21. 367
  22. 904
  23. 766
  24. 157
  25. 609
  26. 566
  27. 441
  28. 590
  29. 1122
  30. 670
  31. 1096
  32. 348
  33. 134
  34. 441
  35. 224
  36. 206
  37. 913
  38. 752
  39. 912
  40. 974

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