Very bad.
It being simple is not a problem, it’s the lack of examples and time control. If you are a college student and you wanted to have a good grade using this app, think twice. Because on my side as a student, you cannot set up an example simulation to correct yourself. Which is a big deal when it’s a sizable grade and your trying to navigate with a fresh mind. You can’t even look up a good example, nobody wants to touch this app.