Khan Academy PC is the official app for Android from the website of the same name, which aims to convey various educational content aimed not only at students, but also at parents and teachers.
To help you understand the content, the service uses videos with objective explanations and captions to make the statements easier to understand. Khan Academy is only available in English, so the subtitles are important and very useful even if you have a command of the language.
The interface is divided into the following subjects: mathematics, natural sciences, economics and finance, and arts and humanities. Each of these is divided into subjects – in Science, for example, you will find topics that are specific to biology, chemistry and physics, among other things.
You can access any topic this way or use the search tool to easily find the app you want. Khan Academy even lets you make a selection with your favorite videos and log in so you can create a user and see their performance in studies.