Warner Bros company plans to assign identification numbers to its employees. Each number is to consist of four different digits from 0 to 9, inclusive, except that the first digit cannot be 0. How many different identification numbers are possible? Choose the correct answer: A) 3,024 B) 4,536 C) 5,040 D) 9,000 E) 10,000
Warner Bros company plans to assign identification numbers to its employees.The first digit can take 9 values from 1 to 9 inclusive;   The second digit can also take 9 values (9 digits minus the one we used for the first digit plus 0);   The third digit can take 8 values;   The fourth digit can take 7 values.   Total = 9*9*8*7 = something with the units digit if 6.   Answer: 4,536.
<result>B</result>
Warner Bros company plans to assign identification numbers to its employees. Each number is to consist of four different digits from 0 to 9, inclusive, except that the first digit cannot be 0. How many different identification numbers are possible?