How many combinations of 9 digit numbers can be produced from the numbers 0 through 9?

How many combinations of 9 digit numbers can be produced from the numbers 0 through 9?
If all numbers can be used as many times as wanted then there are 109 = one billion combinations. If each number can be used only once, there are 10!/(10-9)! = 10!/1! = 10! = 3628800 combinations.

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Clearly answered by someone who does not know the difference between PERMUTATIONS and COMBINATIONS.

The combination 123456789 is the same as the combination 213456789 etc.
All in all, therefore, there are only ten combinations which use each digit at most once.