I'm studying algorithms too right now. As someone who sucks at maths and puzzle solving in general, Steve Skiena's book is proving to be quite approachable for me. Although I have to jump back and forth between the book and Khan Academy to look up some of the Maths. He also has video lectures for the book: https://www3.cs.stonybrook.edu/~skiena/373/videos/ Another thing that helped me was brushing up on C programming…
I also want to recommend Steve Skiena's book. His math section in particular was my own 'ah hah!' moment where I connected math back to the code I wrote. It really unlocks the rest of the book.
Are you referring to section 2, Algorithm Analysis?