There are two types of foreign exchange quotations: European and American. European quotations give the price of a currency in terms of units of another currency, while American quotations give the price in terms of dollars per unit of another currency. Direct quotes give the home currency price per unit of foreign currency, while indirect quotes give the opposite. Cross rates can be calculated using exchange rates between two currencies and a third currency. The TT buying rate is used for clean inward or outward remittances, while the bill buying rate factors in exchange and forward margins to account for delays in collection. The bill selling rate adds an exchange margin to the base rate to cover document handling costs.