Diving Into Math at The Aspen Institute

Just passing along, for the benefit of teachers, a couple of resource sites that I'm not really familiar with, but that were recommended by Jordan Ellenberg and Steven Strogatz (and that's good enough for me) in a recent panel discussion video below at the Aspen Institute:

http://www.artofproblemsolving.com/

https://www.artofmathematics.org/

Jo Boaler was also part of the discussion, and her fairly-well-known site is:  https://www.youcubed.org/

the video is long, almost 80 mins., but very worthwhile if you can find the time: