Euler is a series of challenging mathematical/computer programming
problems that will require more than just mathematical insights to
solve. Although mathematics will help you arrive at elegant and
efficient methods, the use of a computer and programming skills will be
required to solve most problems.
Manipulatives and concept tutorials for mathematics instruction (K -12) emphasis.
a world of math wehre difficult problems can be fun and discover
hundreds of resources, exercises, and an amusement park devoted
exclusively to math.