Ask HN: How can I find math community for my daughter?

My 9 year old daughter loves math and is getting quite good at it (she can derive the quadratic formula from first principles, knows a few other basic proofs, and can factor big numbers faster than I can). Unfortunately, although she has a good number of friends, none of them like to talk about math, so I'm her only "math buddy".

I figured someone here might have some ideas for finding some math community for her. Preferably in-person (in Washington), but virtual could work too. Thanks for any suggestions!