What mobile app actually has the best machine learning tutorials that arent just super basic? I have this big internship interview coming up in exactly six days and I am freaking out a little bit because I need to refresh my memory on some of the core theory before I walk into that room.

I spent some time looking at SoloLearn but it honestly feels a bit too simple, like its mostly just type this variable name or basic python syntax and not really getting into the meat of how the algorithms actually work. I also checked out DataCamp because everyone talks about it but the mobile app version seems like it just gives you these tiny bite-sized puzzles that dont really help me understand the why behind things like backpropagation or random forests.

Plus Im a broke college student in Chicago and I cant really drop thirty bucks right now if its not going to actually help me pass this interview. Im spending about two hours a day on the train for my current retail job and I cant bring my heavy gaming laptop out on the El because there is literally no room to breathe let alone type on a keyboard. Is there anything out there that is more comprehensive or maybe has better interactive lessons that actually feel like youre learning the math and the logic? Or am I just stuck with watching YouTube videos...