← 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 376 · 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. 1.979 − 447 =
  2. 2.756 + 271 =
  3. 3.601 + 641 =
  4. 4.637 + 461 =
  5. 5.514 + 246 =
  6. 6.617 + 245 =
  7. 7.614 − 495 =
  8. 8.679 − 485 =
  9. 9.204 + 214 =
  10. 10.436 + 386 =
  11. 11.671 − 287 =
  12. 12.580 + 409 =
  13. 13.244 + 682 =
  14. 14.420 + 372 =
  15. 15.658 − 298 =
  16. 16.711 + 607 =
  17. 17.531 + 413 =
  18. 18.698 − 454 =
  19. 19.294 + 251 =
  20. 20.412 − 201 =
  21. 21.589 + 511 =
  22. 22.703 + 144 =
  23. 23.583 + 581 =
  24. 24.698 + 136 =
  25. 25.731 − 473 =
  26. 26.807 − 181 =
  27. 27.772 − 236 =
  28. 28.636 + 263 =
  29. 29.399 + 666 =
  30. 30.766 + 571 =
  31. 31.731 − 517 =
  32. 32.185 + 162 =
  33. 33.694 − 205 =
  34. 34.524 + 303 =
  35. 35.200 + 271 =
  36. 36.495 + 199 =
  37. 37.436 − 169 =
  38. 38.557 − 161 =
  39. 39.702 + 168 =
  40. 40.707 − 121 =

Answer key

  1. 532
  2. 1027
  3. 1242
  4. 1098
  5. 760
  6. 862
  7. 119
  8. 194
  9. 418
  10. 822
  11. 384
  12. 989
  13. 926
  14. 792
  15. 360
  16. 1318
  17. 944
  18. 244
  19. 545
  20. 211
  21. 1100
  22. 847
  23. 1164
  24. 834
  25. 258
  26. 626
  27. 536
  28. 899
  29. 1065
  30. 1337
  31. 214
  32. 347
  33. 489
  34. 827
  35. 471
  36. 694
  37. 267
  38. 396
  39. 870
  40. 586

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