[NlightNFotis]

I'm studying the Q31 (BSc Maths) on Open University.

I can second this recommendation. The maths books are _excellent_.

It's hard to explain how, but let me try: most of the maths textbooks I possess (plenty of them) are written with the assumption that you attend lectures at a classroom and use them for extra material/exercises/reference.

The OU books are written with the assumption that you learn from them as the primary material, so they go a lot further with regard to explaining things as well as producing them from first principles.