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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 885 · 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. 1.916 − 266 =
  2. 2.364 + 601 =
  3. 3.605 − 373 =
  4. 4.628 + 408 =
  5. 5.592 − 167 =
  6. 6.831 − 341 =
  7. 7.763 − 447 =
  8. 8.713 − 521 =
  9. 9.660 + 533 =
  10. 10.183 + 652 =
  11. 11.781 − 135 =
  12. 12.424 + 242 =
  13. 13.325 + 498 =
  14. 14.621 − 259 =
  15. 15.426 − 292 =
  16. 16.670 − 156 =
  17. 17.495 − 301 =
  18. 18.414 + 232 =
  19. 19.529 − 163 =
  20. 20.901 − 184 =
  21. 21.508 + 646 =
  22. 22.129 + 588 =
  23. 23.180 + 571 =
  24. 24.723 + 323 =
  25. 25.391 + 201 =
  26. 26.604 − 114 =
  27. 27.133 + 241 =
  28. 28.139 + 184 =
  29. 29.240 + 488 =
  30. 30.718 − 434 =
  31. 31.746 + 115 =
  32. 32.681 − 367 =
  33. 33.771 − 122 =
  34. 34.384 + 638 =
  35. 35.656 − 389 =
  36. 36.444 + 251 =
  37. 37.620 − 131 =
  38. 38.577 − 214 =
  39. 39.852 − 463 =
  40. 40.512 − 188 =

Answer key

  1. 650
  2. 965
  3. 232
  4. 1036
  5. 425
  6. 490
  7. 316
  8. 192
  9. 1193
  10. 835
  11. 646
  12. 666
  13. 823
  14. 362
  15. 134
  16. 514
  17. 194
  18. 646
  19. 366
  20. 717
  21. 1154
  22. 717
  23. 751
  24. 1046
  25. 592
  26. 490
  27. 374
  28. 323
  29. 728
  30. 284
  31. 861
  32. 314
  33. 649
  34. 1022
  35. 267
  36. 695
  37. 489
  38. 363
  39. 389
  40. 324

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