← Add and subtract 3-digit numbers left to right lesson New set →

3-Digit Mental Addition and Subtraction Worksheet

Mental maths lesson 20: Add and subtract 3-digit numbers left to right · Set 582 · 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. 1.165 + 471 =
  2. 2.259 + 116 =
  3. 3.786 + 134 =
  4. 4.591 − 133 =
  5. 5.540 + 301 =
  6. 6.179 + 277 =
  7. 7.314 + 389 =
  8. 8.544 + 298 =
  9. 9.589 − 121 =
  10. 10.439 + 161 =
  11. 11.755 − 131 =
  12. 12.554 + 358 =
  13. 13.457 + 667 =
  14. 14.849 − 349 =
  15. 15.341 + 478 =
  16. 16.695 − 134 =
  17. 17.886 − 264 =
  18. 18.533 + 525 =
  19. 19.219 + 127 =
  20. 20.743 − 395 =
  21. 21.154 + 573 =
  22. 22.949 − 535 =
  23. 23.196 + 511 =
  24. 24.957 − 455 =
  25. 25.913 − 524 =
  26. 26.214 + 452 =
  27. 27.383 + 113 =
  28. 28.646 − 348 =
  29. 29.288 + 574 =
  30. 30.441 − 265 =
  31. 31.934 − 696 =
  32. 32.482 + 338 =
  33. 33.171 + 227 =
  34. 34.838 − 625 =
  35. 35.328 + 309 =
  36. 36.158 + 668 =
  37. 37.759 + 157 =
  38. 38.679 + 237 =
  39. 39.431 − 272 =
  40. 40.469 + 493 =

Answer key

  1. 636
  2. 375
  3. 920
  4. 458
  5. 841
  6. 456
  7. 703
  8. 842
  9. 468
  10. 600
  11. 624
  12. 912
  13. 1124
  14. 500
  15. 819
  16. 561
  17. 622
  18. 1058
  19. 346
  20. 348
  21. 727
  22. 414
  23. 707
  24. 502
  25. 389
  26. 666
  27. 496
  28. 298
  29. 862
  30. 176
  31. 238
  32. 820
  33. 398
  34. 213
  35. 637
  36. 826
  37. 916
  38. 916
  39. 159
  40. 962

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths