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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 535 · 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. 1.176 + 411 =
  2. 2.907 − 249 =
  3. 3.564 + 221 =
  4. 4.439 − 268 =
  5. 5.590 − 489 =
  6. 6.774 + 367 =
  7. 7.504 + 597 =
  8. 8.660 − 197 =
  9. 9.439 − 137 =
  10. 10.273 + 242 =
  11. 11.259 + 623 =
  12. 12.391 + 673 =
  13. 13.656 − 279 =
  14. 14.642 + 625 =
  15. 15.550 + 159 =
  16. 16.744 + 181 =
  17. 17.763 − 601 =
  18. 18.613 + 371 =
  19. 19.180 + 264 =
  20. 20.295 + 201 =
  21. 21.687 − 258 =
  22. 22.608 + 581 =
  23. 23.495 + 507 =
  24. 24.463 − 207 =
  25. 25.877 − 236 =
  26. 26.359 + 471 =
  27. 27.576 − 441 =
  28. 28.799 − 401 =
  29. 29.507 − 151 =
  30. 30.951 − 411 =
  31. 31.618 + 454 =
  32. 32.289 + 452 =
  33. 33.563 − 272 =
  34. 34.525 − 137 =
  35. 35.256 + 248 =
  36. 36.686 − 112 =
  37. 37.588 + 615 =
  38. 38.568 + 504 =
  39. 39.191 + 591 =
  40. 40.363 + 661 =

Answer key

  1. 587
  2. 658
  3. 785
  4. 171
  5. 101
  6. 1141
  7. 1101
  8. 463
  9. 302
  10. 515
  11. 882
  12. 1064
  13. 377
  14. 1267
  15. 709
  16. 925
  17. 162
  18. 984
  19. 444
  20. 496
  21. 429
  22. 1189
  23. 1002
  24. 256
  25. 641
  26. 830
  27. 135
  28. 398
  29. 356
  30. 540
  31. 1072
  32. 741
  33. 291
  34. 388
  35. 504
  36. 574
  37. 1203
  38. 1072
  39. 782
  40. 1024

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