I have had the good fortune of being peripherally involved in efforts in India to explore the use of technology to help children with Autism. read more

This is an amazingly versatile tool to learn Geometry, and in fact most high school math concepts. Single user licences are available as are multiple school user licences for school networks. It is not cheap, but is not the most expensive educational software, either. I ran what turned into being an exremely vibrant course in Geometry, completely by using GSP (as it is affectionately called!) I discovered that basic knowledge was easily accessed, and in a format that was easily adapted to many kinds of problem-solving.