If you want to go out and try some more mathematical approach use the exercises on http://projecteuler.net/ to improve a little on the math side
If you want to understand what the computers does and on what level you just need to start reading books or going to courses
Books about algorithms and data structures (Cormen et al)
Any book introductory to Operating Systems is a must (Tanenbaum or Silberschatz operating systems)
This. I learned to program just by reading a book to get basic syntax and then doing as many Project Euler problems as I could. I got to about 60 and by that point I was ready to try some cool things like making my first app.
If you want to understand what the computers does and on what level you just need to start reading books or going to courses
Books about algorithms and data structures (Cormen et al) Any book introductory to Operating Systems is a must (Tanenbaum or Silberschatz operating systems)