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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 500 · 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. 1.470 − 201 =
  2. 2.706 − 483 =
  3. 3.330 + 275 =
  4. 4.230 + 339 =
  5. 5.522 + 675 =
  6. 6.816 − 686 =
  7. 7.692 + 241 =
  8. 8.486 + 232 =
  9. 9.735 + 481 =
  10. 10.334 + 169 =
  11. 11.428 − 305 =
  12. 12.669 + 615 =
  13. 13.743 + 182 =
  14. 14.598 − 406 =
  15. 15.448 + 322 =
  16. 16.639 + 289 =
  17. 17.755 − 184 =
  18. 18.141 + 281 =
  19. 19.281 + 291 =
  20. 20.125 + 181 =
  21. 21.451 + 323 =
  22. 22.175 + 688 =
  23. 23.681 + 417 =
  24. 24.714 − 554 =
  25. 25.354 + 193 =
  26. 26.481 + 649 =
  27. 27.705 + 672 =
  28. 28.613 − 115 =
  29. 29.875 − 147 =
  30. 30.490 + 307 =
  31. 31.506 − 338 =
  32. 32.624 + 151 =
  33. 33.270 + 183 =
  34. 34.228 + 559 =
  35. 35.630 + 173 =
  36. 36.420 + 272 =
  37. 37.527 − 225 =
  38. 38.208 + 247 =
  39. 39.269 + 459 =
  40. 40.268 + 355 =

Answer key

  1. 269
  2. 223
  3. 605
  4. 569
  5. 1197
  6. 130
  7. 933
  8. 718
  9. 1216
  10. 503
  11. 123
  12. 1284
  13. 925
  14. 192
  15. 770
  16. 928
  17. 571
  18. 422
  19. 572
  20. 306
  21. 774
  22. 863
  23. 1098
  24. 160
  25. 547
  26. 1130
  27. 1377
  28. 498
  29. 728
  30. 797
  31. 168
  32. 775
  33. 453
  34. 787
  35. 803
  36. 692
  37. 302
  38. 455
  39. 728
  40. 623

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