Social Security Number- Permutation?

Question

A social security number consists of nine digits in a particular order, and repetition of digits is allowed. After seeing the last 4 digits printed on a receipt, if you randomly select the other digits what is the probability of getting the correct social security number of the person who was given the receipt?

Answer 1

Since there are still 5 unknown digits, there are 100,000 different permutations of 0-9.