Why is one side of a currency pair used more commonly than the other? For instance the JPY/USD is more commonly used instead of the USD/JPY---why is that the case? However, when it comes to the EURO/USD this is the more preferred way the pair is referenced, as oppossed to the other option USD/EURO--why the seeming inconsistency? In regards to the CNY/USD does this mean that there are 7.26 Yuan for every 1 USD? If so what does the reverse pair mean .137 (monthly average in both cases)? Also if you take the historical monthly avergaes of both sides why are they not statistically identical? For example, the YOY 2005-06 of the JPY/USD from january to january using monthly averages is 12%, with the same time period of USD/JPY being -10%--shouldn`t they theoretically be identical---12% and -12% respectively? A more basic question is which usage denotes the USD as the base currency--USD first or...../USD second? Also, what does the USD/JPY quote of .009217 (monthly average) mean in common exchange usage layman`s terms? The same for USD/CNY regading .13773? And EURO/USD 0.67882 (all monthly averages from January 2008)-I want to know how to properly verbalize this exchange ratio if I was discussing this currency relation in terms of exchanging real money.