The Khan academy (www.khanacademy.org) has plenty of videos and exercises, and if you're looking more at the CS side of things udacity.com runs a few online courses looking at algorithms, discrete maths and the like.
The Khan academy (www.khanacademy.org) has plenty of videos and exercises, and if you're looking more at the CS side of things udacity.com runs a few online courses looking at algorithms, discrete maths and the like.