← 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 219 · 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. 1.629 + 532 =
  2. 2.763 + 116 =
  3. 3.603 + 183 =
  4. 4.160 + 178 =
  5. 5.483 − 298 =
  6. 6.567 − 428 =
  7. 7.931 − 311 =
  8. 8.553 − 252 =
  9. 9.762 − 133 =
  10. 10.567 − 297 =
  11. 11.479 + 435 =
  12. 12.283 + 357 =
  13. 13.859 − 118 =
  14. 14.715 − 151 =
  15. 15.586 + 412 =
  16. 16.515 − 207 =
  17. 17.132 + 451 =
  18. 18.851 − 161 =
  19. 19.459 − 349 =
  20. 20.368 + 416 =
  21. 21.573 + 439 =
  22. 22.371 + 134 =
  23. 23.610 + 185 =
  24. 24.594 − 211 =
  25. 25.426 − 121 =
  26. 26.439 + 352 =
  27. 27.324 + 448 =
  28. 28.168 + 429 =
  29. 29.581 − 446 =
  30. 30.423 + 322 =
  31. 31.599 + 193 =
  32. 32.866 − 251 =
  33. 33.663 + 577 =
  34. 34.302 + 311 =
  35. 35.685 − 147 =
  36. 36.530 − 153 =
  37. 37.462 − 344 =
  38. 38.907 − 737 =
  39. 39.573 + 274 =
  40. 40.449 − 202 =

Answer key

  1. 1161
  2. 879
  3. 786
  4. 338
  5. 185
  6. 139
  7. 620
  8. 301
  9. 629
  10. 270
  11. 914
  12. 640
  13. 741
  14. 564
  15. 998
  16. 308
  17. 583
  18. 690
  19. 110
  20. 784
  21. 1012
  22. 505
  23. 795
  24. 383
  25. 305
  26. 791
  27. 772
  28. 597
  29. 135
  30. 745
  31. 792
  32. 615
  33. 1240
  34. 613
  35. 538
  36. 377
  37. 118
  38. 170
  39. 847
  40. 247

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