I am reading the book Road to Reality by Roger Penrose. However he goes over the maths so fast I don't understand it all, I am studying maths and Further maths and getting over 90% almost all the time so maths normally comes quite easily. What maths topics do I have to know - the contents doesn't really help with knowing what to look up. I would much rather watch a lecture on the topics and understand them in detail. Thank you.