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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 586 · 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. 1.443 − 176 =
  2. 2.192 + 138 =
  3. 3.782 − 365 =
  4. 4.473 − 173 =
  5. 5.299 + 268 =
  6. 6.205 + 478 =
  7. 7.608 + 238 =
  8. 8.523 − 149 =
  9. 9.167 + 511 =
  10. 10.745 − 116 =
  11. 11.621 + 191 =
  12. 12.719 + 607 =
  13. 13.852 − 598 =
  14. 14.349 + 285 =
  15. 15.773 + 372 =
  16. 16.753 + 671 =
  17. 17.665 + 349 =
  18. 18.747 − 437 =
  19. 19.528 + 366 =
  20. 20.550 − 267 =
  21. 21.916 − 151 =
  22. 22.681 − 357 =
  23. 23.703 + 189 =
  24. 24.697 − 231 =
  25. 25.521 + 591 =
  26. 26.965 − 135 =
  27. 27.494 − 186 =
  28. 28.597 − 287 =
  29. 29.226 + 497 =
  30. 30.435 + 191 =
  31. 31.183 + 439 =
  32. 32.141 + 333 =
  33. 33.273 + 344 =
  34. 34.272 + 356 =
  35. 35.832 − 441 =
  36. 36.581 + 567 =
  37. 37.768 + 364 =
  38. 38.236 + 612 =
  39. 39.554 − 186 =
  40. 40.763 − 172 =

Answer key

  1. 267
  2. 330
  3. 417
  4. 300
  5. 567
  6. 683
  7. 846
  8. 374
  9. 678
  10. 629
  11. 812
  12. 1326
  13. 254
  14. 634
  15. 1145
  16. 1424
  17. 1014
  18. 310
  19. 894
  20. 283
  21. 765
  22. 324
  23. 892
  24. 466
  25. 1112
  26. 830
  27. 308
  28. 310
  29. 723
  30. 626
  31. 622
  32. 474
  33. 617
  34. 628
  35. 391
  36. 1148
  37. 1132
  38. 848
  39. 368
  40. 591

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