four numbers for my set 0 to 9 including 0 9 are used to create a personal identification number once a numbers use it cannot be reused how many possible outcomes begin with a 0

All 4 digit numbers beginning with 0, start with 0000 and end with 0999.
The first 100 numbers will always repeat, as they will have more than one 0
The first number will be 0123
From 0100 to 0100 there are no numbers possible
From 0101 to 0999, there are 7 numbers out of every 10 that could be an outcome, 700/1000 numbers are possible
There are 700 out of 1000 that could be outcomes
70%
0.7