European roulette uses a single-zero wheel. The numbers 0 to 36 are arranged around the wheel on numbered compartments. Each number is coloured. Zero is green and the other numbers are either red or black. American roulette uses a wheel with two zeros – zero and double zero. The ball is spun in the opposite direction to that of the wheel. As the ball loses momentum it slows down and eventually drops into one of the numbered slots.
American roulette uses a wheel with two zeros. The numbers are arranged so that consecutive numbers are on opposite sides of the wheel. For example, number 1 is opposite number 2. On one side of the layout, there is a double line between the outside bets and the numbers. This double line denotes where street and double street bets should be placed.