- Blackboard app for Android, iOS
- Linear Algebra by Prof. Gilbert Strang - MIT 18.06
- Russel and Norvig's online AI Class from Stanford - https://www.ai-class.com/
- MIT OpenCourseware Mathematics - http://ocw.mit.edu/courses/mathematics/
- Accessible videos about cryptography - http://www.youtube.com/playlist?list=PLB4D701646DAF0817
- The Google tech dev guide is also a good place to get some practice.