Project Euler is a set of mathmatically-oriented open challenges for developers. I started working my way through these the other day with a bent of using C# and LINQ as much as possible.
I’ve shared my source on my public GitHub
For example: Problem #4 “Find the largest palindrome made from the product of two 3-digit numbers.”
Use of LINQ to express the cartesian join between the sets of 3 digit numbers dramatically simplifies the amount of code written. While the code is somewhat inefficient – I don’t dedupe reflexive pairs of numbers between sets – it is quite elegant.