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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 927 · 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. 1.495 − 318 =
  2. 2.741 + 273 =
  3. 3.467 + 591 =
  4. 4.702 + 291 =
  5. 5.854 − 232 =
  6. 6.758 − 182 =
  7. 7.717 − 151 =
  8. 8.654 + 215 =
  9. 9.421 − 277 =
  10. 10.294 + 498 =
  11. 11.780 − 273 =
  12. 12.129 + 533 =
  13. 13.527 − 419 =
  14. 14.725 − 126 =
  15. 15.882 − 699 =
  16. 16.149 + 673 =
  17. 17.430 − 325 =
  18. 18.156 + 199 =
  19. 19.583 − 262 =
  20. 20.840 − 636 =
  21. 21.155 + 554 =
  22. 22.531 − 161 =
  23. 23.299 + 186 =
  24. 24.825 − 529 =
  25. 25.325 + 552 =
  26. 26.166 + 581 =
  27. 27.370 + 397 =
  28. 28.710 + 426 =
  29. 29.646 + 511 =
  30. 30.950 − 553 =
  31. 31.186 + 151 =
  32. 32.677 − 519 =
  33. 33.391 + 461 =
  34. 34.825 − 599 =
  35. 35.510 + 604 =
  36. 36.281 + 346 =
  37. 37.550 − 184 =
  38. 38.767 + 262 =
  39. 39.633 + 688 =
  40. 40.310 + 457 =

Answer key

  1. 177
  2. 1014
  3. 1058
  4. 993
  5. 622
  6. 576
  7. 566
  8. 869
  9. 144
  10. 792
  11. 507
  12. 662
  13. 108
  14. 599
  15. 183
  16. 822
  17. 105
  18. 355
  19. 321
  20. 204
  21. 709
  22. 370
  23. 485
  24. 296
  25. 877
  26. 747
  27. 767
  28. 1136
  29. 1157
  30. 397
  31. 337
  32. 158
  33. 852
  34. 226
  35. 1114
  36. 627
  37. 366
  38. 1029
  39. 1321
  40. 767

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