The two challenges I appraised were very involved and interesting. They would be quite intriguing to the students in my class. One problem involved volume and the other involved perimeter. Both concepts are relatively new to my students in the way they are presented but will greatly enhance their understanding when completed. If I were able to enhance this site further, I would create a forum for students to share and review the work of other students who are working on a particular challenge.
Children can learn so much from each other and are excited to share their thinking.
Overall, this site will fill a very specific gap in the technology we have available.