Answer:
10 9 8 7
Step-by-step explanation:
There are 10 choices for the first digit,
9 choices for the second digit,
8 choices for the third digit, and
7 choices for the fourth digit.
Using the fundamental counting principle, how many access codes are possible? 5,040
If the digits 0 through 9 could be repeated, how many access codes would be possible? 10,000