FWIW, when entering my CPGE [0] in France, our math teacher asked we forget everything about math except: natural numbers (0, 1, etc.), addition and multiplicat

FWIW, when entering my CPGE [0] in France, our math teacher asked we forget everything about math except: natural numbers (0, 1, etc.), addition and multiplication. Everything needed to be scraped and "taught correctly", and it took only 2 years to get back up to speed (the entire program for the school year is available (in French): https://prepas.org/ups.php?entree=programmes https://prepas.org/ups.php?entree=programmes). Math is incredibly simple to build from scratch (as in: doesn't require a ton of knowledge) [1]. How long it takes for it to "click" though is another matter: I've had a very hard time with calculus and basic logic in first year, and thoroughly failed my second year. I don't have a book to recommend though (everything was taught in class, no textbook); though I remember vaguely some books that others here do recommend. [0] https://en.wikipedia.org/wiki/Classe_pr%C3%A9paratoire_aux_grandes_%C3%A9coles https://en.wikipedia.org/wiki/Classe_pr%C3%A9paratoire_aux_g... [1] https://en.wikipedia.org/wiki/Axiom https://en.wikipedia.org/wiki/Axiom