Mixed-Currency Calculations
It is very possible that your applications will need to add money values of different currencies. The Currency Module provides a money calculator class in the class RWMoneyCalculator<T>.
Before you can use a money calculator class, you must consider and possibly set two policies. The first is the conversion policy, which determines what currency will be used for the result of a mixed-currency calculation. The second is the rounding policy, which determines how the money calculator should round decimal places.