Question: 1. how many possible ip (version 4) addresses are there?
Answer: According to Reserved IP addresses there are 588,514,304 reserved addresses and since there are 4,294,967,296 (2^32) IPv4 addressess in total, there are 3,706,452,992 public addresses. And too many addresses in this post. For IPv4, this pool is 32-bits (232) in size and contains 4,294,967,296 IPv4 addresses.