A CD library.
If you mean having a bunch of CDs that you own, it'd just be your "CD collection".
4 to 3
4: 3
The term CDs is a bit modern to have an established collective noun of its own. A collective noun that suits the situation should be used; for example a set of CDs, a box of CDs, a collection of CDs, etc.
Since there isn't enough data to actually find the number of Cds miriam has, we must simply write and expression for the number of Cds she has. Since Kayla has x Cds and Miriam has seven less;Miriam has x-7 Cds.
it should be about 20 dollars
cds or records, yes. mp3s, I don't think so.
At collection of stamps is refered to as a stamp collection. They are frequently kept in albums. Philately is the name for the study and collection of stamps.
The process of creating MP3s from music CDs is called "ripping".
it is called a range of mountains
a collection of fish is called a school of fish
A collection of fish is called a school.