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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 5 · 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. 1.466 − 191 =
  2. 2.474 − 171 =
  3. 3.542 − 291 =
  4. 4.322 + 241 =
  5. 5.932 − 119 =
  6. 6.311 + 526 =
  7. 7.492 − 199 =
  8. 8.554 − 202 =
  9. 9.447 + 333 =
  10. 10.714 + 645 =
  11. 11.839 − 221 =
  12. 12.729 + 167 =
  13. 13.147 + 158 =
  14. 14.783 + 464 =
  15. 15.161 + 198 =
  16. 16.738 + 123 =
  17. 17.690 + 348 =
  18. 18.137 + 345 =
  19. 19.351 + 496 =
  20. 20.503 + 215 =
  21. 21.600 + 432 =
  22. 22.792 − 535 =
  23. 23.213 + 127 =
  24. 24.420 − 123 =
  25. 25.676 − 203 =
  26. 26.142 + 248 =
  27. 27.565 − 453 =
  28. 28.310 + 449 =
  29. 29.396 + 185 =
  30. 30.335 + 476 =
  31. 31.864 − 193 =
  32. 32.430 + 247 =
  33. 33.300 + 133 =
  34. 34.926 − 698 =
  35. 35.627 − 343 =
  36. 36.332 + 585 =
  37. 37.760 + 301 =
  38. 38.572 − 216 =
  39. 39.704 − 298 =
  40. 40.631 + 179 =

Answer key

  1. 275
  2. 303
  3. 251
  4. 563
  5. 813
  6. 837
  7. 293
  8. 352
  9. 780
  10. 1359
  11. 618
  12. 896
  13. 305
  14. 1247
  15. 359
  16. 861
  17. 1038
  18. 482
  19. 847
  20. 718
  21. 1032
  22. 257
  23. 340
  24. 297
  25. 473
  26. 390
  27. 112
  28. 759
  29. 581
  30. 811
  31. 671
  32. 677
  33. 433
  34. 228
  35. 284
  36. 917
  37. 1061
  38. 356
  39. 406
  40. 810

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