Khan Academy allows you to learn almost anything for free.

Our iOS app is the best way to view Khan Academy’s complete library of over 4,200 videos and articles.

We cover a massive number of topics, including K-12 math, science topics such as biology, chemistry, and physics, and even the humanities with playlists on art history, civics, and finance.

Spend an afternoon brushing up on statistics. Discover how the Krebs cycle works. Learn about the fundamentals of computer science. Prepare for the upcoming SAT. Or, if you’re feeling particularly adventurous, learn how fire stick farming changed the landscape of Australia.

Included in our iPhone and iPad apps:

- Watch all of our 4,200+ videos

- Read articles on topics from Art History to Coach & Classroom Resources

- Track your progress: Log in with your Khan Academy user account to get credit for watching videos, and see your achievements

- Downloadable videos: take individual videos or entire playlists to watch offline at your own pace

Also included in our iPad app:

- Subtitles: follow along, skip ahead, or go back by navigating through subtitles

It doesn't matter if you are a student, teacher, home-schooler, principal, adult returning to the classroom after 20 years, or a friendly alien just trying to get a leg up in earthly biology; Khan Academy's materials and resources are available to you completely free of charge.

Head over to www.khanacademy.org to learn more.