摘要:A system of multiple exchange rates features segmented markets. Segmentation is achieved by the Central Bankcategorizing transactions between residents and non-residents according to the exchange rate at which they areliquidated; and, by impeding exchange rate arbitrage through administrative and other controls. Operationally, itrequires economic agents to use different accounts for each exchange rate. This paper develops the algebra of multipleexchange rates valid for any country with a multiple exchange rate system. It then applies it to Cuba, showing how itssystem boils down algebraically to a simple monetary rule, in which the Central Bank picks (i) the parity between thetwo domestic legal currencies; and (ii) the parity between the convertible domestic currency and foreign currencies, toensure that foreign exchange reserves are not depleted.