 
Summary: http://NLVM.usu.edu
Cointossing under Data Analysis & 912 is
interesting. You can't easily get these statistics
without a computer.
Fill and Pour under Measurement & Grades 35 is a nice
puzzle. How much math is taught?
Note the availability of downloaded Trial Version.
Works for 60 days. Don't know pricing. You can
always use the online site.
http://coolmath.com
The precalc/calc demos are ok, especially
polynomials algebra > polynomials is worth a look,
good example of what they do.
http://shodor.org
Bounded Fraction Pointer is a good example of the
programming expertise and pedagogical ineptitude of the
products. If someone is clever enough to figure out
how to use these tools, they are unlikely to need the
lesson.
http://math.bu.edu/DYSYS/
