representação-numérica

I have seen that software libraries written in C, in general, often use hexadecimal numbers. And Assembly programmers also ne ... mals are also quite present in C macros. Considering the importance of this system, I ask: How do hexadecimal numbers work?

Needed to represent and document an arithmetic algorithm in a mathematical notation, the problem is that I can't find the bes ... p, i += 1). Is this scientific representation right? Or is there another mathematical way to represent a loop of the genre?