http://apps.microsoft.com/windows/en-us/app/004598b2-a5fd-42d2-9a6f-4469eadb782c
The learning application CK-12 offers tutorials and explanations for more than 5,000 math and science concepts.
The app itself is free, and contents can be accessed without account registration.
Available topics include Algebra, Probability and Analysis, Biology, Physics and Chemistry, as well as Engineering, English or History.
[Thank you for the link, J.]
