Math resources are plentiful; broad but shallow
Community Review for Art of Problem Solving
While the resources offered on Art of Problem Solving are vast, the depth of the content itself is quite shallow. Real-world applications of math topics are minimal, and the DOK of most of the problems included in the curricula are 1-2. This site might help students understand more advanced topics, but ironically there is not much true, open-ended "problem solving" to be found.
How I Use It
The Art of Problem Solving site has a host of resources that could be very valuable to teachers. Courses in middle/high school math are offered, as well as a print curriculum for grades 3+ that is aligned to CCSS. There is a wealth of content targeted specifically for students preparing for math contests, which could be very helpful to teachers of advanced courses. One very unique feature of the site is the "community" section, which offers forums based on topic, location, and age group. The most useful feature on the site is the selection of videos, which excellently illustrate the basic foundations of math concepts.