What books would you recommend for an in-depth study of mathematics?

Question

Books

Hello.
I study in the 9th grade and know the school curriculum well (up to the 9th grade, respectively). I would like to study mathematics at a deeper level. What books can you recommend?
I hope for your help, because I have not found something suitable yet.

Answer 1

here about a burning fart and boring wallpapers recently ran through
https://www.mann-ivanov-ferber.ru/books/matematika...
look for the boys in the cart
only carefully: you can turn your brains and then not perceive the university
between us: shcha you you need to take a steam bath in English, and matan is the tenth thing, you don’t need it so much in life

Answer 2

R. Courant, G. Robbins. What is mathematics?
The book is freely available on the MTsNMO website (by the way, there are many good books there).
Not everything will be available there for a 9th grade student, but you can return to such topics later.