Unofficially, the origin of the roulette has been attributed to the mathematician Blaise Pascal. In 1796, he proposed a roulette wheel with 36 numbers well distributed to give both, the casino and the gamblers, high possibilities to win. 50 years later, European casinos added the zero number to give the advantage to the casino. Besides, American casinos added a double zero to increase even more that advantage. This post will describe all important aspects and properties about the zero number (focused on the European roulette) with the purpose of stop fearing it and take advantage of it during betting sessions.