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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 886 · 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. 1.493 − 276 =
  2. 2.549 + 583 =
  3. 3.652 + 116 =
  4. 4.699 − 199 =
  5. 5.182 + 472 =
  6. 6.415 − 274 =
  7. 7.281 + 277 =
  8. 8.722 + 495 =
  9. 9.802 − 622 =
  10. 10.179 + 642 =
  11. 11.858 − 532 =
  12. 12.787 − 454 =
  13. 13.148 + 582 =
  14. 14.148 + 304 =
  15. 15.213 + 456 =
  16. 16.682 − 429 =
  17. 17.168 + 525 =
  18. 18.276 + 341 =
  19. 19.235 + 312 =
  20. 20.444 + 296 =
  21. 21.920 − 261 =
  22. 22.531 − 184 =
  23. 23.742 − 618 =
  24. 24.138 + 251 =
  25. 25.133 + 159 =
  26. 26.884 − 182 =
  27. 27.758 + 221 =
  28. 28.513 − 405 =
  29. 29.986 − 551 =
  30. 30.415 − 141 =
  31. 31.649 − 247 =
  32. 32.717 − 349 =
  33. 33.667 − 476 =
  34. 34.319 + 207 =
  35. 35.622 + 197 =
  36. 36.632 + 266 =
  37. 37.540 − 288 =
  38. 38.499 − 292 =
  39. 39.748 + 501 =
  40. 40.686 + 538 =

Answer key

  1. 217
  2. 1132
  3. 768
  4. 500
  5. 654
  6. 141
  7. 558
  8. 1217
  9. 180
  10. 821
  11. 326
  12. 333
  13. 730
  14. 452
  15. 669
  16. 253
  17. 693
  18. 617
  19. 547
  20. 740
  21. 659
  22. 347
  23. 124
  24. 389
  25. 292
  26. 702
  27. 979
  28. 108
  29. 435
  30. 274
  31. 402
  32. 368
  33. 191
  34. 526
  35. 819
  36. 898
  37. 252
  38. 207
  39. 1249
  40. 1224

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