Math nerds of the atmosphere, kindly check out my brother’s open source collection of free math books, ranging from elementary to precalculus level.
Years of work went into these openly available resources, low-key aiming to subvert a monopolistic & overpriced academic publishing industry.
OpenMathBooks on Bluesky! Will try to reach out with some updates on the project now and then and of course post some cool problems from the books.
Main web page (in Norwegian):
openmath.online
A little less maintained web page (in English):
sindrsh.github.io/openmathbooks/