Each character bets an equal amount of money and then rolls D100. The winner is the character with the highest roll. Successful characters win a sum equal to the number of players multiplied by the sum staked on the game. In the unlikely event of a tie between one or more players, the tying characters make a second bet and roll again. The other characters drop out for that round of betting only.
If gambling in a casino or gaming house, the house adds 10-40% (1D4 x 10) to its roll, depending on how honest the management is. In rigged games, the house may add as much as 60% to its roll, but rarely does so all the time.
Characters with Gamble skill receive a modifier to their roll equal o half their Int score. Characters using spare aces or loaded dice use their Int score unmodified, but stand a chance of being caught. After the results of a round of betting have been declared, the GM should make a secret I test for each participant to see if they spotted any cheating. The test is made with a penalty of -10, unless a cheated character also has Gamble skill, in which case they gain a bonus of +10. Characters caught cheating could be in big trouble!