From the rules...
Roll 2 dice and add the results. If your roll is 3, 4, 9, 10, or 11, you win, and the casino’s boss pays you an amount equal to your bet. If your roll is 2 or 12, the boss must pay you twice what you bet! (If the boss does not have enough money to fully pay off his portion of your bet, you only get the money he does have.)