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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 263 · 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. 1.628 − 163 =
  2. 2.551 − 157 =
  3. 3.281 + 224 =
  4. 4.432 − 231 =
  5. 5.546 − 258 =
  6. 6.227 + 328 =
  7. 7.512 − 345 =
  8. 8.581 + 203 =
  9. 9.438 − 181 =
  10. 10.851 − 343 =
  11. 11.664 + 172 =
  12. 12.507 − 314 =
  13. 13.417 + 431 =
  14. 14.337 + 611 =
  15. 15.540 − 281 =
  16. 16.757 + 152 =
  17. 17.765 − 275 =
  18. 18.157 + 461 =
  19. 19.301 + 689 =
  20. 20.522 + 651 =
  21. 21.741 − 127 =
  22. 22.468 + 163 =
  23. 23.603 − 283 =
  24. 24.467 − 271 =
  25. 25.805 − 287 =
  26. 26.763 + 113 =
  27. 27.973 − 691 =
  28. 28.738 − 328 =
  29. 29.234 + 371 =
  30. 30.150 + 472 =
  31. 31.724 − 372 =
  32. 32.884 − 209 =
  33. 33.709 + 242 =
  34. 34.763 − 222 =
  35. 35.830 − 221 =
  36. 36.377 + 668 =
  37. 37.207 + 427 =
  38. 38.758 + 607 =
  39. 39.684 + 346 =
  40. 40.508 + 165 =

Answer key

  1. 465
  2. 394
  3. 505
  4. 201
  5. 288
  6. 555
  7. 167
  8. 784
  9. 257
  10. 508
  11. 836
  12. 193
  13. 848
  14. 948
  15. 259
  16. 909
  17. 490
  18. 618
  19. 990
  20. 1173
  21. 614
  22. 631
  23. 320
  24. 196
  25. 518
  26. 876
  27. 282
  28. 410
  29. 605
  30. 622
  31. 352
  32. 675
  33. 951
  34. 541
  35. 609
  36. 1045
  37. 634
  38. 1365
  39. 1030
  40. 673

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