Because the wheel, that's spinning, is divided into two equal groups of segments.. win and lose. It may be the case that some people never expect the odds to be accurately reflected, but the illustration of the wheel implies a 50% chance, assuming it's not rigged.

Spin a Win revolves around a wheel that has a total of 53 number spaces. Before each spin, you have 18 seconds to place bets on where you think the wheel will stop. The betting options include main bets, including the 6 different numbers, and side bets, including odd, even, and multipliers.