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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 961 · 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. 1.613 + 426 =
  2. 2.766 + 523 =
  3. 3.466 − 319 =
  4. 4.602 + 532 =
  5. 5.131 + 173 =
  6. 6.675 + 419 =
  7. 7.507 + 311 =
  8. 8.269 + 274 =
  9. 9.490 − 325 =
  10. 10.167 + 256 =
  11. 11.767 + 195 =
  12. 12.588 + 253 =
  13. 13.954 − 265 =
  14. 14.877 − 422 =
  15. 15.274 + 444 =
  16. 16.212 + 201 =
  17. 17.136 + 494 =
  18. 18.631 − 205 =
  19. 19.638 + 284 =
  20. 20.167 + 117 =
  21. 21.639 + 215 =
  22. 22.630 + 158 =
  23. 23.601 − 199 =
  24. 24.198 + 251 =
  25. 25.782 + 526 =
  26. 26.988 − 404 =
  27. 27.605 + 628 =
  28. 28.929 − 471 =
  29. 29.142 + 168 =
  30. 30.979 − 247 =
  31. 31.769 + 638 =
  32. 32.555 − 282 =
  33. 33.426 − 325 =
  34. 34.452 − 293 =
  35. 35.728 + 241 =
  36. 36.967 − 149 =
  37. 37.930 − 391 =
  38. 38.781 − 284 =
  39. 39.335 + 314 =
  40. 40.629 + 455 =

Answer key

  1. 1039
  2. 1289
  3. 147
  4. 1134
  5. 304
  6. 1094
  7. 818
  8. 543
  9. 165
  10. 423
  11. 962
  12. 841
  13. 689
  14. 455
  15. 718
  16. 413
  17. 630
  18. 426
  19. 922
  20. 284
  21. 854
  22. 788
  23. 402
  24. 449
  25. 1308
  26. 584
  27. 1233
  28. 458
  29. 310
  30. 732
  31. 1407
  32. 273
  33. 101
  34. 159
  35. 969
  36. 818
  37. 539
  38. 497
  39. 649
  40. 1084

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