← 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 221 · 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. 1.668 + 361 =
  2. 2.694 + 405 =
  3. 3.851 − 654 =
  4. 4.407 + 423 =
  5. 5.619 + 256 =
  6. 6.671 + 401 =
  7. 7.900 − 308 =
  8. 8.728 − 242 =
  9. 9.707 + 551 =
  10. 10.168 + 528 =
  11. 11.340 + 308 =
  12. 12.816 − 317 =
  13. 13.390 + 373 =
  14. 14.616 + 213 =
  15. 15.514 − 331 =
  16. 16.875 − 269 =
  17. 17.836 − 488 =
  18. 18.158 + 272 =
  19. 19.731 + 395 =
  20. 20.315 + 372 =
  21. 21.537 + 571 =
  22. 22.961 − 434 =
  23. 23.165 + 283 =
  24. 24.733 − 208 =
  25. 25.721 + 385 =
  26. 26.412 − 253 =
  27. 27.606 − 506 =
  28. 28.638 + 549 =
  29. 29.955 − 214 =
  30. 30.567 − 375 =
  31. 31.480 + 215 =
  32. 32.633 + 598 =
  33. 33.223 + 126 =
  34. 34.780 − 274 =
  35. 35.582 + 634 =
  36. 36.172 + 414 =
  37. 37.661 + 167 =
  38. 38.659 − 438 =
  39. 39.136 + 612 =
  40. 40.824 − 353 =

Answer key

  1. 1029
  2. 1099
  3. 197
  4. 830
  5. 875
  6. 1072
  7. 592
  8. 486
  9. 1258
  10. 696
  11. 648
  12. 499
  13. 763
  14. 829
  15. 183
  16. 606
  17. 348
  18. 430
  19. 1126
  20. 687
  21. 1108
  22. 527
  23. 448
  24. 525
  25. 1106
  26. 159
  27. 100
  28. 1187
  29. 741
  30. 192
  31. 695
  32. 1231
  33. 349
  34. 506
  35. 1216
  36. 586
  37. 828
  38. 221
  39. 748
  40. 471

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