The swedish book Mot Bättre Vetande i Matematik by Andrejs Dunkels explains all the maths you need to know to begin studying at the university (meaning all you

The swedish book Mot Bättre Vetande i Matematik by Andrejs Dunkels explains all the maths you need to know to begin studying at the university (meaning all you can learn in primary school + high school and then some) in less than 100 pages A5, no previous knowledge required, with some explanatory cartoons. Cant recommend it enough, made me able to skip class in high school for about a year while still passing the tests with ease. (bad life hack ig)