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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 288 · 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. 1.557 − 225 =
  2. 2.939 − 671 =
  3. 3.957 − 266 =
  4. 4.597 − 437 =
  5. 5.764 − 216 =
  6. 6.685 + 456 =
  7. 7.353 + 449 =
  8. 8.515 − 353 =
  9. 9.531 + 316 =
  10. 10.506 − 149 =
  11. 11.481 − 341 =
  12. 12.683 + 168 =
  13. 13.989 − 304 =
  14. 14.538 − 196 =
  15. 15.588 + 227 =
  16. 16.329 + 359 =
  17. 17.537 − 203 =
  18. 18.412 − 161 =
  19. 19.189 + 681 =
  20. 20.532 + 602 =
  21. 21.540 + 382 =
  22. 22.928 − 267 =
  23. 23.743 + 589 =
  24. 24.483 + 455 =
  25. 25.743 + 563 =
  26. 26.416 − 199 =
  27. 27.295 + 486 =
  28. 28.343 + 132 =
  29. 29.447 + 117 =
  30. 30.428 − 272 =
  31. 31.856 − 322 =
  32. 32.444 + 594 =
  33. 33.143 + 154 =
  34. 34.474 + 541 =
  35. 35.600 + 281 =
  36. 36.777 + 182 =
  37. 37.867 − 176 =
  38. 38.610 + 185 =
  39. 39.228 + 576 =
  40. 40.357 + 448 =

Answer key

  1. 332
  2. 268
  3. 691
  4. 160
  5. 548
  6. 1141
  7. 802
  8. 162
  9. 847
  10. 357
  11. 140
  12. 851
  13. 685
  14. 342
  15. 815
  16. 688
  17. 334
  18. 251
  19. 870
  20. 1134
  21. 922
  22. 661
  23. 1332
  24. 938
  25. 1306
  26. 217
  27. 781
  28. 475
  29. 564
  30. 156
  31. 534
  32. 1038
  33. 297
  34. 1015
  35. 881
  36. 959
  37. 691
  38. 795
  39. 804
  40. 805

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