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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 179 · 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. 1.746 + 209 =
  2. 2.642 − 282 =
  3. 3.394 + 403 =
  4. 4.520 − 251 =
  5. 5.154 + 529 =
  6. 6.574 + 553 =
  7. 7.534 − 353 =
  8. 8.436 − 168 =
  9. 9.293 + 273 =
  10. 10.438 + 332 =
  11. 11.539 − 344 =
  12. 12.160 + 423 =
  13. 13.811 − 691 =
  14. 14.427 − 143 =
  15. 15.469 − 339 =
  16. 16.603 + 213 =
  17. 17.743 − 241 =
  18. 18.422 − 178 =
  19. 19.986 − 172 =
  20. 20.320 + 431 =
  21. 21.486 − 129 =
  22. 22.716 − 131 =
  23. 23.679 + 441 =
  24. 24.259 + 281 =
  25. 25.637 + 576 =
  26. 26.498 + 229 =
  27. 27.294 + 137 =
  28. 28.824 − 307 =
  29. 29.931 − 151 =
  30. 30.876 − 259 =
  31. 31.148 + 296 =
  32. 32.697 + 657 =
  33. 33.570 + 631 =
  34. 34.769 − 306 =
  35. 35.644 + 521 =
  36. 36.687 + 485 =
  37. 37.497 + 427 =
  38. 38.775 − 327 =
  39. 39.653 + 578 =
  40. 40.252 + 331 =

Answer key

  1. 955
  2. 360
  3. 797
  4. 269
  5. 683
  6. 1127
  7. 181
  8. 268
  9. 566
  10. 770
  11. 195
  12. 583
  13. 120
  14. 284
  15. 130
  16. 816
  17. 502
  18. 244
  19. 814
  20. 751
  21. 357
  22. 585
  23. 1120
  24. 540
  25. 1213
  26. 727
  27. 431
  28. 517
  29. 780
  30. 617
  31. 444
  32. 1354
  33. 1201
  34. 463
  35. 1165
  36. 1172
  37. 924
  38. 448
  39. 1231
  40. 583

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