← 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 343 · 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. 1.618 − 401 =
  2. 2.629 + 557 =
  3. 3.190 + 446 =
  4. 4.623 − 234 =
  5. 5.527 − 322 =
  6. 6.427 − 273 =
  7. 7.832 − 401 =
  8. 8.800 − 451 =
  9. 9.778 + 147 =
  10. 10.442 + 152 =
  11. 11.712 − 317 =
  12. 12.298 + 591 =
  13. 13.313 + 294 =
  14. 14.980 − 838 =
  15. 15.883 − 464 =
  16. 16.430 − 154 =
  17. 17.917 − 692 =
  18. 18.743 + 242 =
  19. 19.375 + 418 =
  20. 20.472 − 249 =
  21. 21.771 − 444 =
  22. 22.811 − 493 =
  23. 23.446 − 185 =
  24. 24.171 + 128 =
  25. 25.619 − 295 =
  26. 26.668 + 202 =
  27. 27.148 + 628 =
  28. 28.882 − 291 =
  29. 29.631 − 301 =
  30. 30.594 − 428 =
  31. 31.498 + 513 =
  32. 32.756 + 181 =
  33. 33.382 + 191 =
  34. 34.819 − 622 =
  35. 35.177 + 332 =
  36. 36.945 − 321 =
  37. 37.596 + 553 =
  38. 38.532 + 509 =
  39. 39.307 + 271 =
  40. 40.964 − 251 =

Answer key

  1. 217
  2. 1186
  3. 636
  4. 389
  5. 205
  6. 154
  7. 431
  8. 349
  9. 925
  10. 594
  11. 395
  12. 889
  13. 607
  14. 142
  15. 419
  16. 276
  17. 225
  18. 985
  19. 793
  20. 223
  21. 327
  22. 318
  23. 261
  24. 299
  25. 324
  26. 870
  27. 776
  28. 591
  29. 330
  30. 166
  31. 1011
  32. 937
  33. 573
  34. 197
  35. 509
  36. 624
  37. 1149
  38. 1041
  39. 578
  40. 713

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