One of the greatest unsolved problems in mathematics was whether any map needed more than 4 colours assuming that no regions which shared an edge…

Game for 1-4 players. Rules:If one of the roles was a “1” the player scores zero points, otherwise the player scores the sum of his…

“Tài Wù, oh great ancestor, tell us – will the first day of the week will be unlucky?” Gu took the red hot poker and…

How many of you are there?How many parents do you have?How many grandparents?How many great grandparents?How many great great grandparents?How many great great great grandparents?How…

Find 3 positive integers x, y and z which satisfy this equation: Using this solution, find a different solution by changing one and only one…

Just like in the problem Mirror, Mirror in the Box, a triangular box plays tricks with light. Mirrors reflect light beams that hit them obliquely…

Frogs have a saying: “The Other Lily Pad Is Always Greener”. Some green and yellow frogs were arguing about this until they agreed that they…

The Dragon of Ignorance has three heads and three tails. You can slay it with the Sword of Knowledge, by chopping off all its heads…

On Thursday January 20th the Pocono Mountain region experienced the first big snow storm of the new millennium. Many schools closed because of the slippery…

Coyotes demarcate their territory by peeing on bushes, rocks, shrubs, cacti, trees, and anything else that is lying around. It is tiring, never-ending work. That…