I have been waiting to come across such a website like coolmath.com.
It has everything for a math teacher. Of course, the actual target viewers are students but I think even parents who teach their children mathematics can use the site frequently.
As a mathematics teacher,I could always use mathematical games and puzzles. math problems that require to be solved mentally and quickly are great math teaching aids.
Coolmath has a ton of cool math games and puzzles, lots of really clear math lessons (Algebra and fractions), fractals, Calculus, Geometry, tessellations and more.
As Coolmath.com has aptly described, it is an amusement park for mathematics.The site is colorful with big fonts and it is fun browsing the coolmath.com