First dozen / Premiere douzaine: numbers 1 - 12 (On the French-style mat, the square marked 12P) Middle dozen / Moyenne douzaine: numbers 13 - 24 (On the French-style mat, the square marked 12M) Last dozen / Dernier douzaine: numbers 25 - 36 (On the French-style mat, the square marked 12D)

In square 12P or P12. On the middle 12 numbers, i.e. 12M or M12 (13-24) 2 to 1. In square 12M or M12. On the last 12 numbers, i.e. 12D or D12 (25-36)

The 0  (single zero) and the 00  (double zero) are the green slots on the roulette wheel. These pockets could receive a 35:1 payout if hit straight up. If there's a split, the payout could be 17:1. This type of bet is somewhat risky, but the payouts could be worth it.

What are the odds of hitting green in roulette? The odds for green in roulette depend on the version of the game. Since the American wheel has two green pockets, the odds of hitting either of them are 2-in-38, or 5.26%. In the European format, this drops to just 2.70% since there is one only green pocket on the wheel.