When they were first introduced, postal zip codes were five digit numbers, theoretically ranging from $00000$ to $99999$. (In reality, the lowest zip code was $00601$ for San Juan, Puerto Rico; the highest was $ 99950$ for Ketchikan, Alaska.) An additional four digit have been added, so each zip code is now a nine digit number. How many zip codes are at least as large as 60000-0000, are even numbers, and have a $7$ as their third digit?
Attempt: $A1*A2*A3*...*A9$ be a zip code. With $A3 = 7$. I don't know how to continue.
Can someone please help me with this problem? Thanks