"MyOpenMath runs on the free, open source, IMathAS platform, providing free hosted use of this platform in support of free, open textbooks. The intent is to provide classroom use of the platform, without any required cost to students, for schools wanting a managed install of the IMathAS platform, and to provide students self-study opportunities."
Project 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.