Hi, 

At the moment, only videos can be bookmarked and downloaded from the mobile app. If you have limited access to the Internet, limited data, or need to use Khan Academy in a permanently disconnected environment, I suggest you try the offline version of Khan Academy: Kolibri!

This is an ed-tech platform created by Learning Equality to provide a version of the Khan Academy videos and exercises that works offline. Running Kolibri (previously KA Lite) as a local server, you can watch Khan Academy videos and complete exercises - all without needing an internet connection!

Hope this helps!