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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 554 · 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. 1.711 − 355 =
  2. 2.774 + 637 =
  3. 3.833 − 722 =
  4. 4.698 − 346 =
  5. 5.455 − 154 =
  6. 6.834 − 325 =
  7. 7.229 + 116 =
  8. 8.131 + 204 =
  9. 9.721 − 176 =
  10. 10.808 − 249 =
  11. 11.956 − 563 =
  12. 12.500 + 674 =
  13. 13.260 + 121 =
  14. 14.413 − 121 =
  15. 15.643 + 255 =
  16. 16.552 − 446 =
  17. 17.626 − 424 =
  18. 18.241 + 213 =
  19. 19.515 − 321 =
  20. 20.473 + 673 =
  21. 21.202 + 651 =
  22. 22.328 + 321 =
  23. 23.200 + 468 =
  24. 24.143 + 279 =
  25. 25.293 + 527 =
  26. 26.783 + 285 =
  27. 27.851 − 235 =
  28. 28.492 − 316 =
  29. 29.520 − 277 =
  30. 30.553 − 451 =
  31. 31.729 − 501 =
  32. 32.627 + 621 =
  33. 33.690 + 561 =
  34. 34.660 − 278 =
  35. 35.137 + 251 =
  36. 36.933 − 243 =
  37. 37.921 − 261 =
  38. 38.238 + 192 =
  39. 39.776 + 297 =
  40. 40.673 + 431 =

Answer key

  1. 356
  2. 1411
  3. 111
  4. 352
  5. 301
  6. 509
  7. 345
  8. 335
  9. 545
  10. 559
  11. 393
  12. 1174
  13. 381
  14. 292
  15. 898
  16. 106
  17. 202
  18. 454
  19. 194
  20. 1146
  21. 853
  22. 649
  23. 668
  24. 422
  25. 820
  26. 1068
  27. 616
  28. 176
  29. 243
  30. 102
  31. 228
  32. 1248
  33. 1251
  34. 382
  35. 388
  36. 690
  37. 660
  38. 430
  39. 1073
  40. 1104

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