Honing a skill takes practice and coding is no different. Websites with coding problems help you learn, grow, and achieve your coding goals.

Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve.

The Project Euler website presents literally hundreds of mathematical / computer programming problems that range in difficulty from “well, that's not-so-hard” to “my brains are leaking out of my ears!