“Arithmancy” is their name for math classes and is mentioned several times throughout the books. It is one of Hermione’s favorite subjects.

At one point, the real world evil witch that is JK Rowling suggested that Arithmancy is like dviniation, but with math, saying they use numbers to predict the future. I take this to mean that the wizarding community discovered calculus independently from the rest of the world and mistook it for a new form of magic.

dedicated nas systems are pretty overpriced imo, often costing as much or more than the drives you put in them. much cheaper to build your own. depending on your needs, this can be as simple as a raspberry pi plus an external hard drive.