[killaken2000]

I would prefer it be more explicit and say, "each digit can only be used once".

Different can be interpreted in multiple ways.

Reminds me of a physics test where the question is something like:

Susie is almost at her house and comes to a stop in 4 seconds. What was her acceleration.

[edflsafoiewq]

The only other interpretation that is obvious to me is "not all of the digits can be the same", but 990 is not an available answer.