Roulette is a casino game in which a small ball rolls around a wheel and players place bets on the number or type of number it will land on. It has offered glamour, mystery and excitement to casino-goers since the 17th century. Its rules are relatively simple, but it provides a surprising depth of strategy for serious bettors.

The mathematics of Roullete is based on probability, the study of how likely it is that an event will occur. This probability is calculated by dividing the total number of possible outcomes by the total number of outcomes that have already occurred. The results of this calculation are then used to predict the odds of a specific outcome occurring, or the likelihood that an event will occur, in the future.

A roulette wheel consists of a solid wooden disk slightly convex in shape, with a series of metal partitions or frets around the edge. These compartments are called pockets and they alternately appear red and black. There is also a green pocket marked 0, and on American roulette wheels a second green one numbered 00.

During a game of roulette, a croupier spins the wheel and then rolls a small ball onto the wheel in the direction of a pocket that has been chosen by the player. When the ball has stopped spinning, the croupier removes all losing bets from the table and pays out winning bets according to the payout table. Then the player places new chips on the betting grid and the process begins anew.

In order to play roulette, you must choose your bets carefully and stick to them. Each table carries a placard that describes the minimum and maximum bets allowed. This is usually followed by a chart that shows the odds of each bet and how much it pays if you win.

A good rule of thumb is to start with outside bets, which are easier to hit and pay more. These bets include odd/even, red/black, and low/high. You should also avoid using the Martingale betting system, which involves doubling your stake after every loss and then resetting it to the original amount after a win. This system is effective for games with even money payouts, but it is not suitable for other casino games.