As a fun wedding after-party activity, my cousin Channy arranged for a set of casino tables to show up in the evening and handed out funny-money to play with. My dad and I decided to learn a new game and met up at the Craps table. I figured my math/gamer friends might find it interesting to puzzle over play strategies.

The game:

Everyone places at least the minimum bet on an area of the table called the pass line.

As the round begins a shooter (dice roller) is chosen. The shooter hands the dice to the left on subsequent rounds.

During the “Come out” phase, the shooter makes one or more rolls. If the shooter rolls 2, 3 or 12, the dealer takes all the pass line money and the round ends. If the shooter rolls 7 or 11, everyone’s money on the pass line is doubled. If the shooter rolls a 4, 5, 6, 8, 9, or 10, this number becomes “the point”.

Once a point is chosen, point bets can be made or rescinded by placing your wager into boxes numbered 3-11 (without a 7). Any subsequent rolls by the shooter will double the money of anyone’s bet in the corresponding number. If the shooter rolls “the point” number, everyone’s money on the pass line is doubled. If the shooter rolls a 7, the round ends and the dealer collects all the money still on the table.

The goal is to wager on numbers that the shooter will roll before a seven comes up. There are a bunch of special-case rules (one-off bets, rare odds bets, etc) that don’t significantly change the structure of the game, but change from table to table depending on the rules you’re playing by.

The results:

The math in Craps is neat and tidy. You’ll quickly see that it’s a losing game – like most casino games there’s no case where the odds are in your favor. You have marginally better odds playing the 6 or 8, which are second only in rolling frequency to the 7. Wikipedia have a good breakdown of various bet odds, and they’re all bad. It’s telling that they include a section devoted to calculations of “Loss per hour”.

It didn’t take me long to blow through my pile of funny money, while watching people around me get lucky breaks all evening. My strategy was to cover 6 and 8, usually two at a time, but our table threw a statistically improbable number of 9s, making the superstitious folks with bad math skills at the table filthy rich. Mathematicians make terrible gamblers, I guess.

The game ended when a guy who’d won big at the poker table descended on our game late in the evening and bet everything he had on number 5, and it came up for him, bankrupting the dealer and pretty much finishing off our game.

It’s actually a fun game, with lots of minor winning going on while your chip pile slowly bleeds to death. You’ll have a slight edge if you’ve ever puzzled out dice-rolling odds during a tedious game of Dungeons and Dragons. If you’re looking to actually win money, though, you’re almost definitely better off playing Poker or Blackjack. (…or bet it all on the 5!)