Right, which was what I was getting at. The person I responded to had written: > Knuth has even written a book, Concrete Mathematics, that covers these pre-req

Right, which was what I was getting at. The person I responded to had written: > Knuth has even written a book, Concrete Mathematics, that covers these pre-requisites but it might be faster and easier to watch a Khan Academy video! Which suggests KA as an alternative to CM. Which doesn't follow if it doesn't cover the same material.