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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 44 · 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. 1.764 + 222 =
  2. 2.284 + 468 =
  3. 3.744 − 193 =
  4. 4.544 + 665 =
  5. 5.152 + 191 =
  6. 6.601 − 179 =
  7. 7.699 − 514 =
  8. 8.482 − 242 =
  9. 9.967 − 131 =
  10. 10.643 − 325 =
  11. 11.126 + 127 =
  12. 12.488 − 295 =
  13. 13.554 − 398 =
  14. 14.484 + 121 =
  15. 15.674 − 167 =
  16. 16.664 − 544 =
  17. 17.725 + 311 =
  18. 18.500 − 233 =
  19. 19.769 − 271 =
  20. 20.421 − 131 =
  21. 21.610 − 217 =
  22. 22.413 + 665 =
  23. 23.803 − 255 =
  24. 24.718 − 486 =
  25. 25.753 − 179 =
  26. 26.879 − 267 =
  27. 27.772 + 239 =
  28. 28.288 + 431 =
  29. 29.504 − 186 =
  30. 30.179 + 164 =
  31. 31.393 + 489 =
  32. 32.836 − 712 =
  33. 33.522 − 398 =
  34. 34.776 + 636 =
  35. 35.653 + 661 =
  36. 36.257 + 564 =
  37. 37.961 − 772 =
  38. 38.411 + 378 =
  39. 39.179 + 657 =
  40. 40.456 + 465 =

Answer key

  1. 986
  2. 752
  3. 551
  4. 1209
  5. 343
  6. 422
  7. 185
  8. 240
  9. 836
  10. 318
  11. 253
  12. 193
  13. 156
  14. 605
  15. 507
  16. 120
  17. 1036
  18. 267
  19. 498
  20. 290
  21. 393
  22. 1078
  23. 548
  24. 232
  25. 574
  26. 612
  27. 1011
  28. 719
  29. 318
  30. 343
  31. 882
  32. 124
  33. 124
  34. 1412
  35. 1314
  36. 821
  37. 189
  38. 789
  39. 836
  40. 921

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