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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 534 · 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. 1.609 − 208 =
  2. 2.602 + 492 =
  3. 3.956 − 156 =
  4. 4.911 − 589 =
  5. 5.159 + 488 =
  6. 6.531 − 114 =
  7. 7.658 + 601 =
  8. 8.388 + 675 =
  9. 9.441 − 124 =
  10. 10.413 − 245 =
  11. 11.417 − 145 =
  12. 12.445 − 178 =
  13. 13.804 − 391 =
  14. 14.690 − 199 =
  15. 15.222 + 594 =
  16. 16.649 + 429 =
  17. 17.463 − 251 =
  18. 18.972 − 504 =
  19. 19.142 + 603 =
  20. 20.365 + 651 =
  21. 21.460 − 334 =
  22. 22.633 − 376 =
  23. 23.502 − 121 =
  24. 24.401 + 653 =
  25. 25.340 + 184 =
  26. 26.512 + 267 =
  27. 27.628 + 397 =
  28. 28.665 + 159 =
  29. 29.670 + 458 =
  30. 30.867 − 434 =
  31. 31.245 + 341 =
  32. 32.209 + 152 =
  33. 33.849 − 159 =
  34. 34.858 − 272 =
  35. 35.491 + 352 =
  36. 36.139 + 278 =
  37. 37.623 − 487 =
  38. 38.246 + 353 =
  39. 39.929 − 259 =
  40. 40.354 + 399 =

Answer key

  1. 401
  2. 1094
  3. 800
  4. 322
  5. 647
  6. 417
  7. 1259
  8. 1063
  9. 317
  10. 168
  11. 272
  12. 267
  13. 413
  14. 491
  15. 816
  16. 1078
  17. 212
  18. 468
  19. 745
  20. 1016
  21. 126
  22. 257
  23. 381
  24. 1054
  25. 524
  26. 779
  27. 1025
  28. 824
  29. 1128
  30. 433
  31. 586
  32. 361
  33. 690
  34. 586
  35. 843
  36. 417
  37. 136
  38. 599
  39. 670
  40. 753

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