How I Use It
I use it mostly as a tool for fast finishers. Since it cannot be tailored to meet certain lessons and activities, I allow this site as a choice for "free time". The math fact and Pre-Algebra section is nice as well.
I have used this with all ages, including those younger than 4th grade who are more advanced learners. They really like the foreign language component, since we do not offer languages until 6th grade.