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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 733 · 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. 1.130 + 168 =
  2. 2.806 − 619 =
  3. 3.688 − 236 =
  4. 4.212 + 289 =
  5. 5.175 + 141 =
  6. 6.647 − 317 =
  7. 7.676 − 367 =
  8. 8.148 + 512 =
  9. 9.979 − 481 =
  10. 10.447 − 222 =
  11. 11.658 + 183 =
  12. 12.435 − 131 =
  13. 13.407 + 351 =
  14. 14.313 + 387 =
  15. 15.287 + 273 =
  16. 16.653 + 344 =
  17. 17.697 + 327 =
  18. 18.483 + 155 =
  19. 19.464 − 301 =
  20. 20.865 − 112 =
  21. 21.673 + 299 =
  22. 22.530 + 234 =
  23. 23.282 + 186 =
  24. 24.983 − 125 =
  25. 25.367 + 387 =
  26. 26.655 + 373 =
  27. 27.955 − 721 =
  28. 28.968 − 684 =
  29. 29.135 + 185 =
  30. 30.488 + 147 =
  31. 31.747 + 674 =
  32. 32.584 − 411 =
  33. 33.754 + 521 =
  34. 34.909 − 731 =
  35. 35.823 − 238 =
  36. 36.418 + 231 =
  37. 37.376 + 582 =
  38. 38.258 + 663 =
  39. 39.497 + 532 =
  40. 40.774 − 581 =

Answer key

  1. 298
  2. 187
  3. 452
  4. 501
  5. 316
  6. 330
  7. 309
  8. 660
  9. 498
  10. 225
  11. 841
  12. 304
  13. 758
  14. 700
  15. 560
  16. 997
  17. 1024
  18. 638
  19. 163
  20. 753
  21. 972
  22. 764
  23. 468
  24. 858
  25. 754
  26. 1028
  27. 234
  28. 284
  29. 320
  30. 635
  31. 1421
  32. 173
  33. 1275
  34. 178
  35. 585
  36. 649
  37. 958
  38. 921
  39. 1029
  40. 193

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