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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 823 · 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. 1.481 − 246 =
  2. 2.558 − 202 =
  3. 3.498 + 654 =
  4. 4.357 + 445 =
  5. 5.442 − 263 =
  6. 6.460 + 397 =
  7. 7.541 + 153 =
  8. 8.417 − 295 =
  9. 9.487 + 374 =
  10. 10.773 + 577 =
  11. 11.621 + 661 =
  12. 12.217 + 551 =
  13. 13.347 + 373 =
  14. 14.348 + 212 =
  15. 15.530 + 385 =
  16. 16.159 + 228 =
  17. 17.276 + 271 =
  18. 18.734 + 568 =
  19. 19.581 − 121 =
  20. 20.398 + 225 =
  21. 21.824 − 275 =
  22. 22.460 − 287 =
  23. 23.259 + 614 =
  24. 24.802 − 355 =
  25. 25.462 + 556 =
  26. 26.415 + 578 =
  27. 27.167 + 406 =
  28. 28.510 + 407 =
  29. 29.370 + 233 =
  30. 30.490 + 421 =
  31. 31.435 + 505 =
  32. 32.206 + 368 =
  33. 33.447 − 274 =
  34. 34.739 − 592 =
  35. 35.926 − 237 =
  36. 36.722 − 585 =
  37. 37.478 − 219 =
  38. 38.425 − 262 =
  39. 39.485 − 183 =
  40. 40.461 − 256 =

Answer key

  1. 235
  2. 356
  3. 1152
  4. 802
  5. 179
  6. 857
  7. 694
  8. 122
  9. 861
  10. 1350
  11. 1282
  12. 768
  13. 720
  14. 560
  15. 915
  16. 387
  17. 547
  18. 1302
  19. 460
  20. 623
  21. 549
  22. 173
  23. 873
  24. 447
  25. 1018
  26. 993
  27. 573
  28. 917
  29. 603
  30. 911
  31. 940
  32. 574
  33. 173
  34. 147
  35. 689
  36. 137
  37. 259
  38. 163
  39. 302
  40. 205

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