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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 532 · 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. 1.625 − 392 =
  2. 2.776 + 282 =
  3. 3.256 + 653 =
  4. 4.748 + 256 =
  5. 5.909 − 196 =
  6. 6.484 + 587 =
  7. 7.902 − 543 =
  8. 8.639 − 514 =
  9. 9.896 − 124 =
  10. 10.771 + 321 =
  11. 11.473 + 402 =
  12. 12.639 − 401 =
  13. 13.687 + 464 =
  14. 14.580 + 338 =
  15. 15.478 − 276 =
  16. 16.664 + 539 =
  17. 17.432 − 137 =
  18. 18.281 + 486 =
  19. 19.606 − 244 =
  20. 20.654 + 526 =
  21. 21.550 − 128 =
  22. 22.377 + 612 =
  23. 23.247 + 113 =
  24. 24.584 + 181 =
  25. 25.424 + 521 =
  26. 26.695 + 228 =
  27. 27.642 − 311 =
  28. 28.156 + 561 =
  29. 29.524 + 425 =
  30. 30.919 − 211 =
  31. 31.451 + 379 =
  32. 32.700 − 447 =
  33. 33.296 + 415 =
  34. 34.619 − 288 =
  35. 35.475 − 155 =
  36. 36.930 − 488 =
  37. 37.734 + 278 =
  38. 38.209 + 476 =
  39. 39.307 + 366 =
  40. 40.587 − 464 =

Answer key

  1. 233
  2. 1058
  3. 909
  4. 1004
  5. 713
  6. 1071
  7. 359
  8. 125
  9. 772
  10. 1092
  11. 875
  12. 238
  13. 1151
  14. 918
  15. 202
  16. 1203
  17. 295
  18. 767
  19. 362
  20. 1180
  21. 422
  22. 989
  23. 360
  24. 765
  25. 945
  26. 923
  27. 331
  28. 717
  29. 949
  30. 708
  31. 830
  32. 253
  33. 711
  34. 331
  35. 320
  36. 442
  37. 1012
  38. 685
  39. 673
  40. 123

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