How does the browser display the same web page whether you enter the URL or the IP address?

Answer 1

This is the whole idea of HTTP, we don't easily as humans remember a sequence of numbers, for our most used sites, and it makes for poor memorability. IP addresses came first, and are the way of computers understanding addresses for websites, you may see Google.com (Or whatever example) but your browser translates this into something it can understand e.g. an IP address. by putting in an IP you basically just bypass the translation usually done whenever you go to a web address.

Answer 2

The IP address is the actual or real address of the location on the internet. But, because these long numbers are clumsy and hard to remember they're given nicknames or pseudonyms (called URLs) that are easier to remember and use. When your browser sends your Internet service provider a URL they have a database where they look up the nickname you gave and get the real IP address to know where to go. This database/lookup table is called a Name Server, because when given a name it gives back an IP address. If your browser send the IP address they don't need to go through this extra step and simply go directly to the address.