A betting system is a particular method of betting that is believed, in the long run, to have an advantage over the house. Several systems have been proposed over the past centuries and the most widely known of these is probably the Martingale.

Originally used to refer to a class of betting strategies in 18th-century France, the term Martingale is now known as a betting strategy in which one doubles the bet after every loss; given an infinite wealth without a betting limit, the Martingale user will recover from a string of losses once he makes a win and will gain a betting unit on his consecutive wins.

Example: Pep (Martingale user) bets one dollar on heads in a coin flip. If he wins, he will bet another dollar on the next coin flip and so forth. If he loses, he will double his bet and flip again. If he loses again, he will double his last bet and so forth, until he flips heads. Once Pep makes a win, he will recover his losses and lower his bet back to one dollar.

When applied to casinos, the Martingale and other betting systems will elicit one response from genuine mathematicians and statisticians: “They are all equally worthless!” Aside from the betting limits set by casinos, nobody actually has an infinite amount of wealth. Therefore, while the Martingale might seem promising at first glance, a gambler is just as likely to take down a casino by performing mind control on a deck of cards.