Learning things is great, but a high-quality education usually costs money. Not so in the age of Khan Academy. Thanks to charitable contributions from the likes of Google and The Bill and Melinda Gates Foundation, you can learn about anything from basic biology to multivariable calculus for free. Now you can do it on Android with the new official beta app for Khan Academy.

Khan Academy materials are mostly in the form of videos, which are hosted on YouTube. The app and website add things like progress tracking and full transcripts. The app is currently somewhat limited—it doesn't appear to have practice exercises or any sort of teaching tools, which are available on the website. I'd really like to see Chromecast support too. Still, it's probably a better option than the unofficial Viewer for Khan Academy we covered before.

You can try the app by opting into the beta right here (the app links below won't work until you've joined). There's a G+ community, but it's optional for this one. We also have it on APK Mirror. This is still a work in progress, but the basic functionality seems to be there.