A company has assigned a distinct 3-digit code number to each of its 330 employees. Each code number was formed from the digits
$$2, 3, 4, 5, 6, 7, 8, 9$$
and no digit appears more than once in any one code number. How many unassigned code numbers are there?
6
58
174
182
399
本题的关键是理解题意 总共可以的组合有8*7*6=336个 总共有330名员工 所以多余6个