After searching the site, i found some questions like mine, but none fits my case.
I am a 11th grade student, and i have an ebook reader(kindle). I would like to know where can i find(free) content about intermediate math learning, so i could spend some spare time (when away from the computer) studying.
The ideal is .mobi's, but .pdf's are also fine.
I already looked MIT OCW pdf's, but i don't understand a lot, and i don't know from where should i start.
I found an awesome website made by a free foundation. The site of the CK-12 foundation (http://www.ck12.org) seems to have lots of content, ordered by section.
All of the content is free licensed under CC licenses, and has an option to download for Kindle/iPad or PDF for offline viewing.
While sites like the gutemberg project and MIT OCW have lots of content, but mostly they're incomprehensible for a eleventh grade student, this site seems to be a simplification, and everything is very acessible to read.
I'll give it a try for a few days, then i'll leave some feedback. I still have hope to find more resources. Every answer helps ;)