← 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 292 · 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. 1.720 − 357 =
  2. 2.788 + 355 =
  3. 3.600 − 398 =
  4. 4.389 + 271 =
  5. 5.712 − 605 =
  6. 6.917 − 117 =
  7. 7.738 − 251 =
  8. 8.519 − 391 =
  9. 9.507 − 312 =
  10. 10.638 − 135 =
  11. 11.696 + 504 =
  12. 12.730 + 303 =
  13. 13.752 + 268 =
  14. 14.401 + 671 =
  15. 15.535 + 317 =
  16. 16.223 + 421 =
  17. 17.701 + 661 =
  18. 18.431 − 281 =
  19. 19.447 − 157 =
  20. 20.435 − 117 =
  21. 21.650 − 275 =
  22. 22.465 − 215 =
  23. 23.781 + 268 =
  24. 24.358 + 374 =
  25. 25.209 + 117 =
  26. 26.574 + 595 =
  27. 27.981 − 193 =
  28. 28.978 − 805 =
  29. 29.964 − 211 =
  30. 30.799 − 554 =
  31. 31.616 + 361 =
  32. 32.689 + 418 =
  33. 33.728 − 376 =
  34. 34.521 − 123 =
  35. 35.527 − 325 =
  36. 36.533 + 671 =
  37. 37.652 − 392 =
  38. 38.521 − 208 =
  39. 39.715 + 268 =
  40. 40.661 + 351 =

Answer key

  1. 363
  2. 1143
  3. 202
  4. 660
  5. 107
  6. 800
  7. 487
  8. 128
  9. 195
  10. 503
  11. 1200
  12. 1033
  13. 1020
  14. 1072
  15. 852
  16. 644
  17. 1362
  18. 150
  19. 290
  20. 318
  21. 375
  22. 250
  23. 1049
  24. 732
  25. 326
  26. 1169
  27. 788
  28. 173
  29. 753
  30. 245
  31. 977
  32. 1107
  33. 352
  34. 398
  35. 202
  36. 1204
  37. 260
  38. 313
  39. 983
  40. 1012

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