← 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 617 · 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. 1.770 + 437 =
  2. 2.238 + 611 =
  3. 3.658 − 233 =
  4. 4.734 + 211 =
  5. 5.488 + 261 =
  6. 6.323 + 557 =
  7. 7.190 + 443 =
  8. 8.134 + 195 =
  9. 9.453 − 114 =
  10. 10.594 − 412 =
  11. 11.784 + 217 =
  12. 12.711 + 178 =
  13. 13.319 + 505 =
  14. 14.725 − 419 =
  15. 15.170 + 606 =
  16. 16.144 + 317 =
  17. 17.783 − 187 =
  18. 18.637 + 666 =
  19. 19.547 − 438 =
  20. 20.509 + 367 =
  21. 21.412 − 304 =
  22. 22.583 + 224 =
  23. 23.512 − 302 =
  24. 24.488 − 184 =
  25. 25.709 + 485 =
  26. 26.597 + 236 =
  27. 27.704 + 172 =
  28. 28.775 − 253 =
  29. 29.612 − 263 =
  30. 30.760 − 449 =
  31. 31.723 − 441 =
  32. 32.625 − 466 =
  33. 33.206 + 445 =
  34. 34.616 − 353 =
  35. 35.849 − 163 =
  36. 36.672 − 121 =
  37. 37.267 + 268 =
  38. 38.702 − 241 =
  39. 39.982 − 186 =
  40. 40.565 + 138 =

Answer key

  1. 1207
  2. 849
  3. 425
  4. 945
  5. 749
  6. 880
  7. 633
  8. 329
  9. 339
  10. 182
  11. 1001
  12. 889
  13. 824
  14. 306
  15. 776
  16. 461
  17. 596
  18. 1303
  19. 109
  20. 876
  21. 108
  22. 807
  23. 210
  24. 304
  25. 1194
  26. 833
  27. 876
  28. 522
  29. 349
  30. 311
  31. 282
  32. 159
  33. 651
  34. 263
  35. 686
  36. 551
  37. 535
  38. 461
  39. 796
  40. 703

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