Money is a broad term that refers to any financial instrument that can fulfill the functions of money. These financial instruments together are collectively referred to as the money supply of an economy. Since the money supply consists of various financial instruments (usually currency, demand deposits and various other types of deposits), the amount of money in an economy is measured by adding together these financial instruments creating a monetary aggregate. Finance is the science of funds management. The general areas of finance are business finance, personal finance, and public finance. Finance includes saving money and often includes lending money. The field of finance deals with the concepts of time, money, risk and how they are interrelated. It also deals with how money is spent and budgeted.