A roulette wheel has 36 slots, numbered from 1 to 36. The wheel is spun by a small motor, and the ball is dropped into one of the slots. If the ball falls into a black slot, that number is selected as the bet, and play moves on to the next slot.
If the ball falls into a red slot, the player loses his bet and play moves on to the next slot. The object of the game is to predict which number the ball will fall into next. .
The size of a roulette wheel can vary, but they are typically about 18 inches in diameter. The number of slots on a roulette wheel also varies, but they are typically around 18 or 20.
