← 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 531 · 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. 1.470 + 629 =
  2. 2.710 + 255 =
  3. 3.706 − 191 =
  4. 4.834 − 578 =
  5. 5.516 + 651 =
  6. 6.451 + 245 =
  7. 7.333 + 182 =
  8. 8.592 − 238 =
  9. 9.468 − 207 =
  10. 10.194 + 126 =
  11. 11.403 + 194 =
  12. 12.263 + 601 =
  13. 13.530 − 311 =
  14. 14.168 + 561 =
  15. 15.410 + 519 =
  16. 16.359 + 541 =
  17. 17.190 + 615 =
  18. 18.526 + 356 =
  19. 19.697 − 457 =
  20. 20.167 + 206 =
  21. 21.262 + 117 =
  22. 22.242 + 351 =
  23. 23.740 + 191 =
  24. 24.221 + 512 =
  25. 25.269 + 312 =
  26. 26.735 + 394 =
  27. 27.252 + 491 =
  28. 28.879 − 701 =
  29. 29.780 + 555 =
  30. 30.443 − 207 =
  31. 31.462 − 149 =
  32. 32.432 + 371 =
  33. 33.864 − 303 =
  34. 34.307 + 182 =
  35. 35.458 − 235 =
  36. 36.500 − 192 =
  37. 37.870 − 371 =
  38. 38.465 + 514 =
  39. 39.778 + 258 =
  40. 40.277 + 387 =

Answer key

  1. 1099
  2. 965
  3. 515
  4. 256
  5. 1167
  6. 696
  7. 515
  8. 354
  9. 261
  10. 320
  11. 597
  12. 864
  13. 219
  14. 729
  15. 929
  16. 900
  17. 805
  18. 882
  19. 240
  20. 373
  21. 379
  22. 593
  23. 931
  24. 733
  25. 581
  26. 1129
  27. 743
  28. 178
  29. 1335
  30. 236
  31. 313
  32. 803
  33. 561
  34. 489
  35. 223
  36. 308
  37. 499
  38. 979
  39. 1036
  40. 664

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