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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 932 · 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. 1.132 + 525 =
  2. 2.600 − 238 =
  3. 3.666 + 165 =
  4. 4.914 − 193 =
  5. 5.232 + 561 =
  6. 6.329 + 213 =
  7. 7.634 + 196 =
  8. 8.607 − 113 =
  9. 9.569 + 288 =
  10. 10.651 − 161 =
  11. 11.910 − 176 =
  12. 12.253 + 399 =
  13. 13.561 + 659 =
  14. 14.253 + 641 =
  15. 15.375 + 629 =
  16. 16.504 − 326 =
  17. 17.397 + 629 =
  18. 18.725 − 424 =
  19. 19.538 + 474 =
  20. 20.606 + 277 =
  21. 21.852 − 752 =
  22. 22.633 − 431 =
  23. 23.223 + 511 =
  24. 24.493 + 392 =
  25. 25.393 + 499 =
  26. 26.142 + 674 =
  27. 27.595 − 364 =
  28. 28.652 − 546 =
  29. 29.891 − 585 =
  30. 30.310 + 451 =
  31. 31.622 − 469 =
  32. 32.429 + 376 =
  33. 33.732 − 461 =
  34. 34.637 − 324 =
  35. 35.627 + 242 =
  36. 36.198 + 173 =
  37. 37.352 + 261 =
  38. 38.193 + 219 =
  39. 39.243 + 624 =
  40. 40.509 − 376 =

Answer key

  1. 657
  2. 362
  3. 831
  4. 721
  5. 793
  6. 542
  7. 830
  8. 494
  9. 857
  10. 490
  11. 734
  12. 652
  13. 1220
  14. 894
  15. 1004
  16. 178
  17. 1026
  18. 301
  19. 1012
  20. 883
  21. 100
  22. 202
  23. 734
  24. 885
  25. 892
  26. 816
  27. 231
  28. 106
  29. 306
  30. 761
  31. 153
  32. 805
  33. 271
  34. 313
  35. 869
  36. 371
  37. 613
  38. 412
  39. 867
  40. 133

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