You can trade in a vast number of permutations of freely floating currencies. Many traders choose to focus on one or two major currency pairs so they build a good level of expertise and knowledge of those currencies, their trading patterns and successful strategies. Examples of major currency pairs include the pound and the dollar, the euro and the dollar or the dollar and the yen. These are called majors because they account for the bulk of trading. Because demand for and the supply of these currencies is so vast it is easy to buy and sell positions.