I absolutely LOVE Khan Academy! They offer so many things to learn and everything is FREE! I visit the site frequently just to refresh my math skills and learn things! My 6th grade daughter plays there often as well.
They just announced they are partnering with the College Board to provide free SAT prep to everyone on planet earth! If you’re planning on taking the SAT now, or in the next few years, you MUST “click here” and read what they are doing!
Khan Academy totally ROCKS!