website: http://projecteuler.net/
What is Project Euler?
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.
I am learning to code after a decade. I am using the problems from Project Euler to learn a new programming language, currently Python.