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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 162 · 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. 1.725 − 272 =
  2. 2.287 + 581 =
  3. 3.461 − 183 =
  4. 4.384 + 485 =
  5. 5.469 + 381 =
  6. 6.255 + 293 =
  7. 7.911 − 686 =
  8. 8.153 + 142 =
  9. 9.267 + 326 =
  10. 10.421 + 212 =
  11. 11.617 + 342 =
  12. 12.445 + 549 =
  13. 13.794 − 305 =
  14. 14.850 − 342 =
  15. 15.449 − 172 =
  16. 16.494 + 262 =
  17. 17.607 − 159 =
  18. 18.159 + 645 =
  19. 19.208 + 611 =
  20. 20.332 + 478 =
  21. 21.648 + 448 =
  22. 22.583 − 361 =
  23. 23.614 − 501 =
  24. 24.328 + 651 =
  25. 25.657 − 183 =
  26. 26.499 + 248 =
  27. 27.318 + 569 =
  28. 28.554 − 264 =
  29. 29.747 + 563 =
  30. 30.647 − 451 =
  31. 31.458 − 158 =
  32. 32.578 − 386 =
  33. 33.456 + 154 =
  34. 34.566 + 657 =
  35. 35.623 + 131 =
  36. 36.470 + 252 =
  37. 37.676 − 231 =
  38. 38.506 − 153 =
  39. 39.717 − 324 =
  40. 40.975 − 313 =

Answer key

  1. 453
  2. 868
  3. 278
  4. 869
  5. 850
  6. 548
  7. 225
  8. 295
  9. 593
  10. 633
  11. 959
  12. 994
  13. 489
  14. 508
  15. 277
  16. 756
  17. 448
  18. 804
  19. 819
  20. 810
  21. 1096
  22. 222
  23. 113
  24. 979
  25. 474
  26. 747
  27. 887
  28. 290
  29. 1310
  30. 196
  31. 300
  32. 192
  33. 610
  34. 1223
  35. 754
  36. 722
  37. 445
  38. 353
  39. 393
  40. 662

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