Equation of exchange
In monetary economics, the equation of exchange is the relation: M ⋅ V = P ⋅ Q {\displaystyle M\cdot V=P\cdot Q} where, for a given period, M {\displaystyle M\,} is the total money supply in circulation on average in an economy. V {\displaystyle V\,} is the velocity of money, that is the average frequency with which a unit of money is spent.