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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 205 · 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. 1.628 + 552 =
  2. 2.810 − 471 =
  3. 3.745 − 534 =
  4. 4.759 + 586 =
  5. 5.719 − 213 =
  6. 6.496 + 464 =
  7. 7.528 − 316 =
  8. 8.601 − 497 =
  9. 9.649 + 575 =
  10. 10.595 − 456 =
  11. 11.419 − 285 =
  12. 12.427 − 266 =
  13. 13.154 + 396 =
  14. 14.160 + 228 =
  15. 15.176 + 487 =
  16. 16.690 − 113 =
  17. 17.534 − 176 =
  18. 18.171 + 124 =
  19. 19.981 − 351 =
  20. 20.693 + 626 =
  21. 21.468 − 202 =
  22. 22.720 + 227 =
  23. 23.840 − 181 =
  24. 24.330 + 625 =
  25. 25.427 + 558 =
  26. 26.192 + 451 =
  27. 27.752 + 466 =
  28. 28.659 − 162 =
  29. 29.463 − 164 =
  30. 30.788 + 494 =
  31. 31.770 + 687 =
  32. 32.567 + 139 =
  33. 33.722 − 357 =
  34. 34.705 + 265 =
  35. 35.416 + 269 =
  36. 36.510 − 368 =
  37. 37.647 + 611 =
  38. 38.456 − 122 =
  39. 39.422 + 624 =
  40. 40.473 + 251 =

Answer key

  1. 1180
  2. 339
  3. 211
  4. 1345
  5. 506
  6. 960
  7. 212
  8. 104
  9. 1224
  10. 139
  11. 134
  12. 161
  13. 550
  14. 388
  15. 663
  16. 577
  17. 358
  18. 295
  19. 630
  20. 1319
  21. 266
  22. 947
  23. 659
  24. 955
  25. 985
  26. 643
  27. 1218
  28. 497
  29. 299
  30. 1282
  31. 1457
  32. 706
  33. 365
  34. 970
  35. 685
  36. 142
  37. 1258
  38. 334
  39. 1046
  40. 724

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