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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 318 · 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. 1.726 − 189 =
  2. 2.504 + 678 =
  3. 3.903 − 664 =
  4. 4.464 + 236 =
  5. 5.159 + 633 =
  6. 6.774 + 191 =
  7. 7.278 + 223 =
  8. 8.870 − 226 =
  9. 9.367 + 306 =
  10. 10.822 − 159 =
  11. 11.683 − 572 =
  12. 12.471 − 371 =
  13. 13.677 − 132 =
  14. 14.249 + 481 =
  15. 15.881 − 611 =
  16. 16.491 + 116 =
  17. 17.415 + 288 =
  18. 18.504 + 396 =
  19. 19.370 + 492 =
  20. 20.492 − 164 =
  21. 21.869 − 667 =
  22. 22.867 − 224 =
  23. 23.720 − 153 =
  24. 24.914 − 499 =
  25. 25.665 − 472 =
  26. 26.806 − 213 =
  27. 27.538 + 195 =
  28. 28.913 − 802 =
  29. 29.321 + 355 =
  30. 30.765 + 162 =
  31. 31.660 + 491 =
  32. 32.311 + 407 =
  33. 33.789 + 176 =
  34. 34.728 − 261 =
  35. 35.426 + 486 =
  36. 36.675 + 653 =
  37. 37.773 + 448 =
  38. 38.567 − 195 =
  39. 39.842 − 433 =
  40. 40.751 − 221 =

Answer key

  1. 537
  2. 1182
  3. 239
  4. 700
  5. 792
  6. 965
  7. 501
  8. 644
  9. 673
  10. 663
  11. 111
  12. 100
  13. 545
  14. 730
  15. 270
  16. 607
  17. 703
  18. 900
  19. 862
  20. 328
  21. 202
  22. 643
  23. 567
  24. 415
  25. 193
  26. 593
  27. 733
  28. 111
  29. 676
  30. 927
  31. 1151
  32. 718
  33. 965
  34. 467
  35. 912
  36. 1328
  37. 1221
  38. 372
  39. 409
  40. 530

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