Student easily understand maths concept through 3D animation.
i found the website link : http://www.designmate.com/video_designmate_maths.html
Liked the experimental way the value of Pi and the formula for the circumference was approximated as the best way to introduce the concept.
Not enough demos to illustrate the product correctly.
Never, never, ever, cripple any product in any way for your demo. That ugly watermark, smack dab in the middle, interferes and ruins the vids. I or anyone I know never purchases a product that we cannot see in it's entirety first. Crippled software aggravates the heck out of me. Do a time trial on a limited number (more than 2) vids, no ugly, distracting watermarks.
In mathematics, you don't understand things. You just get used to them.
I agree with you regarding the satisfaction and importance of actually computing some numbers. I can't tell you how often I see time and money wasted because someone didn't bother to run the numbers.
It would Be nice to Have to something like that on here.