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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 6 · 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. 1.761 + 467 =
  2. 2.383 + 536 =
  3. 3.491 − 251 =
  4. 4.192 + 566 =
  5. 5.464 − 246 =
  6. 6.586 − 362 =
  7. 7.556 − 447 =
  8. 8.149 + 541 =
  9. 9.237 + 414 =
  10. 10.481 − 153 =
  11. 11.539 − 115 =
  12. 12.546 − 224 =
  13. 13.668 − 181 =
  14. 14.507 − 361 =
  15. 15.736 + 151 =
  16. 16.739 − 136 =
  17. 17.738 − 208 =
  18. 18.436 + 336 =
  19. 19.386 + 331 =
  20. 20.595 + 619 =
  21. 21.605 + 141 =
  22. 22.297 + 165 =
  23. 23.724 + 302 =
  24. 24.259 + 626 =
  25. 25.709 + 456 =
  26. 26.571 − 401 =
  27. 27.552 + 452 =
  28. 28.240 + 329 =
  29. 29.413 − 257 =
  30. 30.546 + 279 =
  31. 31.564 − 201 =
  32. 32.982 − 268 =
  33. 33.528 − 348 =
  34. 34.156 + 671 =
  35. 35.669 + 184 =
  36. 36.503 + 381 =
  37. 37.478 − 289 =
  38. 38.457 − 211 =
  39. 39.933 − 331 =
  40. 40.402 + 143 =

Answer key

  1. 1228
  2. 919
  3. 240
  4. 758
  5. 218
  6. 224
  7. 109
  8. 690
  9. 651
  10. 328
  11. 424
  12. 322
  13. 487
  14. 146
  15. 887
  16. 603
  17. 530
  18. 772
  19. 717
  20. 1214
  21. 746
  22. 462
  23. 1026
  24. 885
  25. 1165
  26. 170
  27. 1004
  28. 569
  29. 156
  30. 825
  31. 363
  32. 714
  33. 180
  34. 827
  35. 853
  36. 884
  37. 189
  38. 246
  39. 602
  40. 545

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