Ever heard of permutations? You wouldn’t be here if you weren’t interested, right? Well permutations are the number of configurations you can get out of a given set of values that require the factoring in of order.
From owning a combination lock with 3 digits I am pretty sure, there are 1000 (10^3) permutations. (000, 001, 002, … 999). Maybe, your result applies only in the specific case, when there must not be combinations with same digits (e.g 880, 112).