I just found this tonight though some of you might already know of the site. Basically this one man himself has put all the K-12 curriculum plus College curriculum online with very short videos, about 10 minutes; that will help you with pretty much anything you're missing out on from bad teachers, not understanding concepts or ADD.
Site is here: Khan Academy
Little background on the guy: He's a MIT graduate who went into financial, hedge funds etc. Quit his paying job to do this solo. Bill Gates I believe has funded him as well as other people. It's kind of revolutionary. I suggest watching this video: Salman Khan Talk: MIT Club of Northern California
In addition to these videos there are exercises in the link page of videos and there's also an exercise link that will take you through Arithmetic all the way to Trig/Some Calculus, haven't done them myself but plan on starting from Arithmetic.
Also there's MIT Open Courseware that are free online courses that students pay tens of thousands of dollars for that are free. I'm sure there's other stuff. I plan on going into community college this fall myself and becoming an Electrical Engineer eventually from Florida State University. This site will probably help get me there and once I do, I hope someday too that I can give back to society like this man has. If anyone deserves the highest humanity award it is someone like him.
Sorry for the wall of text, I hope that someone actually was helped by this. Honestly I think anyone who goes through all these lessons will be years ahead of your average high school or college student. The MIT video is long but worth watching. Eye opening for anyone who is interested.
Edited, Feb 10th 2011 4:16am by Excenmille: I need to learn how to write correctly apparently. Suggestions?
Edited, Feb 10th 2011 10:20am by Excenmille