The number quoted for these prices is based on the current exchange rate of the currencies in the pair, or how much of the second currency you would get in exchange for one unit of the first currency (for instance, if 1 EUR could be exchanged for 1.68 USD, the bid and ask price would be on either side of this number). Learn more about Forex quotes in this article: Understanding and Reading Forex Quotes.
Foreign exchange fixing is the daily monetary exchange rate fixed by the national bank of each country. The idea is that central banks use the fixing time and exchange rate to evaluate the behavior of their currency. Fixing exchange rates reflect the real value of equilibrium in the market. Banks, dealers, and traders use fixing rates as a market trend indicator.
One unique aspect of this international market is that there is no central marketplace for foreign exchange. Rather, currency trading is conducted electronically over-the-counter (OTC), which means that all transactions occur via computer networks between traders around the world, rather than on one centralized exchange. The market is open 24 hours a day, five and a half days a week, and currencies are traded worldwide in the major financial centers of London, New York, Tokyo, Zurich, Frankfurt, Hong Kong, Singapore, Paris and Sydney—across almost every time zone. This means that when the trading day in the U.S. ends, the forex market begins anew in Tokyo and Hong Kong. As such, the forex market can be extremely active any time of the day, with price quotes changing constantly.