Editing Roulette (section)

===D'Alembert system===
The system, also called {{Lang|fr|montant et demontant}} (from French, meaning upwards and downwards), is often called a pyramid system. It is based on a mathematical equilibrium theory devised by [[Jean le Rond d'Alembert|a French mathematician of the same name]]. Like the martingale, this system is mainly applied to the even-money outside bets, and is favored by players who want to keep the amount of their bets and losses to a minimum. The betting progression is very simple: After each loss, one unit is added to the next bet, and after each win, one unit is deducted from the next bet. Starting with an initial bet of, say, 1 unit, a loss would raise the next bet to 2 units. If this is followed by a win, the next bet would be 1 units.

This betting system relies on the gambler's fallacy—that the player is more likely to lose following a win, and more likely to win following a loss.