When we look at an IP address like “18.104.22.168”, the left prefix is the “Network Number”, so in a sense we read IP addresses from left to right, where the left part of the IP address is the most general part of the address and right part of the address is most specific:
Broad —-> Narrow
For domain names, we read from right to left: drchuck.personal.si.umich.edu
Narrow <— Broad
The most general part of this domain name is “.edu”, which means higher education institutions. The subdomain “umich.edu” is a particular higher education institution.