I think you have to show interest about it yourself. If you aren't curious about it, he/she probably won't either. From time to time I talk children in my fami

I think you have to show interest about it yourself. If you aren't curious about it, he/she probably won't either. From time to time I talk children in my family about mathematical subjects I myself find interesting, and I know something about, such as strange stuff about infinite, mathematical logic, or crazy and counter-intuitive mathematical theorems. And they keep interested about it as long as I do. So I think that can be a way.