Learn Maths Fast: Khan Academy
If you want to learn basic maths fast, there is Khan Academy, which regroups a lot of videos made on simple maths topics with interactive tests to see how your doing on a particular topic. Basically, you are done with a topic if you give 10 good answers in a row in the interactive test.
See bellow, a video introduction by its creator.
This works greatly and I hope the site will have more advanced topics in maths and in computer science in the future.