How do I learn a new subject quickly with AI without fooling myself that I understand it?

The trap is that a clear AI explanation feels like understanding. In a study of nearly a thousand high school maths students, plain GPT-4 raised practice grades by 48%, but once it was taken away those students did 17% worse than students who never had it; a tutor version that gave hints instead of answers largely removed that harm. So make the AI test you. Try the problem before asking, ask for a hint rather than the solution, have it quiz you one question at a time, and explain the idea back in your own words while it looks for gaps. Come back a few days later and ask for fresh questions. If you can only do it with the chat open, you have not learned it yet.