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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 981 · 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. 1.491 − 125 =
  2. 2.722 − 478 =
  3. 3.164 + 212 =
  4. 4.663 + 461 =
  5. 5.442 + 582 =
  6. 6.162 + 564 =
  7. 7.560 − 321 =
  8. 8.596 + 503 =
  9. 9.594 − 326 =
  10. 10.676 − 194 =
  11. 11.225 + 593 =
  12. 12.327 + 612 =
  13. 13.679 + 278 =
  14. 14.730 − 566 =
  15. 15.241 + 139 =
  16. 16.520 + 471 =
  17. 17.677 + 297 =
  18. 18.532 − 222 =
  19. 19.427 − 301 =
  20. 20.571 + 563 =
  21. 21.660 + 225 =
  22. 22.768 + 541 =
  23. 23.617 − 395 =
  24. 24.438 + 461 =
  25. 25.422 − 218 =
  26. 26.630 − 406 =
  27. 27.210 + 281 =
  28. 28.255 + 121 =
  29. 29.759 + 671 =
  30. 30.751 + 626 =
  31. 31.725 + 123 =
  32. 32.673 − 157 =
  33. 33.782 + 571 =
  34. 34.723 + 457 =
  35. 35.594 + 481 =
  36. 36.479 − 352 =
  37. 37.185 + 617 =
  38. 38.827 − 361 =
  39. 39.407 + 217 =
  40. 40.723 − 289 =

Answer key

  1. 366
  2. 244
  3. 376
  4. 1124
  5. 1024
  6. 726
  7. 239
  8. 1099
  9. 268
  10. 482
  11. 818
  12. 939
  13. 957
  14. 164
  15. 380
  16. 991
  17. 974
  18. 310
  19. 126
  20. 1134
  21. 885
  22. 1309
  23. 222
  24. 899
  25. 204
  26. 224
  27. 491
  28. 376
  29. 1430
  30. 1377
  31. 848
  32. 516
  33. 1353
  34. 1180
  35. 1075
  36. 127
  37. 802
  38. 466
  39. 624
  40. 434

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