Showing what's behind the curtain

Find how many Pythagorean triangles allow tiling with a perimeter < 100,000,000.

The prime factorisation of binomial coefficients

Powers With Trailing Digits

Right triangles with integer coordinates

Finding Nim positions consisting of heap sizes n, 2n and 3n for n ≤ 2^{30} that result in a losing game.

Solve SuDoku puzzles

An unexpected way of using two cubes to make a square.

Make plurals of English words from the given input

Build a fence to maximize an area enclosed between the fence and a fixed wall

Add two reversed numbers and output their reversed sum