The typical "American" roulette wheel is divided into 38 slots which are numbered 1 to 36 plus 0 and 00. Even numbers are red and odd numbers black. 0 and 00 are green. Some casinos offer the "European Wheel". This wheel has only 37 slots. There is no 00.

After you place your bets, the dealer spins a small white ball in the opposite direction of the turning wheel. When the ball comes to rest in one of the slots, the dealer will call out the winning number and settle all bets.

Betting

These are the bets you can place and their corresponding payouts:

Straight bet

A bet on a single number pays 35:1

Split bet

A bet on 2 adjacent numbers pays 17:1

Street bet

A bet on 3 numbers on a horizontal line pays 11:1

Corner bet

A bet on a block of 4 numbers pays 8:1

Line bet

A bet on 6 numbers in 2 adjacent rows pays 5:1

Column bet

A bet on 1 of 3 vertical columns pays 2:1

Dozen bet

A bet on 12 numbers, low (1-12), middle (13-24) or high (25-36) pays 2:1

Even bet

A bet on even or odd, red or black, low (1-18) or high (19-36) pays 1:1

Some casinos use a rule called en prison. When a zero or double zero hits, the player loses half the bet, or can let the bet remain in play, with the results to be determined on the next spin. This rule only applies to even money bets.Odds

With the 38-number American wheel, the house has a big 5.26 percent edge. (Whenever 0 or 00 are hit, all bets lose.)

With the 37-number European wheel, the house advantage is 2.7 percent. In other words, on every $100 bet the house makes $2.70. With the en prison rule, this edge drops to just 1.35 percent.

Obviously you want to look for casinos that offer the European, single-zero wheel -- and many online casinos do. If you can find one that also offers en prison, so much the better.