I had this rare privilege of being able to pursue in my adult life, what had been my childhood dream.

The greatest problem for mathematicians now is probably the Riemann Hypothesis.

Some mathematics problems look simple, and you try them for a year or so, and then you try them for a hundred years, and it turns out that they're extremely hard to solve. There's no reason why these problems shouldn't be easy, and yet they turn out to be extremely intricate. Fermat's Last Theorem is the most beautiful example of this.

Always try the problem that matters most to you.

I tried to fit it in with some previous broad conceptual understanding of some part of mathematics that would clarify the particular problem I was thinking about.

The definition of a good mathematical problem is the mathematics it generates rather than the problem itself.

But the best problem I ever found, I found in my local public library.