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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 895 · 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. 1.909 − 562 =
  2. 2.621 + 677 =
  3. 3.631 + 251 =
  4. 4.410 + 686 =
  5. 5.201 + 371 =
  6. 6.735 − 343 =
  7. 7.309 + 649 =
  8. 8.384 + 294 =
  9. 9.351 + 206 =
  10. 10.436 + 669 =
  11. 11.480 − 329 =
  12. 12.283 + 441 =
  13. 13.366 + 314 =
  14. 14.524 − 282 =
  15. 15.399 + 364 =
  16. 16.145 + 221 =
  17. 17.619 + 207 =
  18. 18.457 + 684 =
  19. 19.981 − 754 =
  20. 20.731 + 185 =
  21. 21.812 − 435 =
  22. 22.454 − 311 =
  23. 23.423 − 185 =
  24. 24.908 − 325 =
  25. 25.238 + 321 =
  26. 26.583 + 119 =
  27. 27.386 + 502 =
  28. 28.202 + 164 =
  29. 29.324 + 612 =
  30. 30.722 − 619 =
  31. 31.279 + 303 =
  32. 32.142 + 411 =
  33. 33.661 + 207 =
  34. 34.785 + 121 =
  35. 35.206 + 608 =
  36. 36.606 + 246 =
  37. 37.496 + 148 =
  38. 38.655 − 501 =
  39. 39.137 + 429 =
  40. 40.545 − 134 =

Answer key

  1. 347
  2. 1298
  3. 882
  4. 1096
  5. 572
  6. 392
  7. 958
  8. 678
  9. 557
  10. 1105
  11. 151
  12. 724
  13. 680
  14. 242
  15. 763
  16. 366
  17. 826
  18. 1141
  19. 227
  20. 916
  21. 377
  22. 143
  23. 238
  24. 583
  25. 559
  26. 702
  27. 888
  28. 366
  29. 936
  30. 103
  31. 582
  32. 553
  33. 868
  34. 906
  35. 814
  36. 852
  37. 644
  38. 154
  39. 566
  40. 411

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