Which of the following are proper network (not host) addresses?

1. 192.168.23.0/24
2. 193.205.16.132/26
3. 172.16.4.0/20
4. 10.57.13.64/28

How can I tell? What is a proper network address?

Is a proper network address when the IP address is the same as the network address? For example in the first one that is the case.