trading is very expensive in a bart

trading is very expensive in a barter economy.people must spend a lot of time and effort finding others with whom they can made mutually satisfactory swaps.since time and effort are scarce resources a barter economy simpler and more efficient.the unit account is the unit which prices are kept.in Britain prices are quoted in pounds sterling ,in France ,in french francs.it is usually convenient to use the units in which the medium of exchange is measured as the unit of account as well.however there are exceptions.during the rapid german inflation of 1922-23 when prices in marks were changing very quickly ,german shopkeepers found it more convenient to use dollar as the unit of account.prices were quoted in dollars even though payment was made in marks ,the german medium of exchange .money is a store of value because it can be used to make purchases in the future.to be accepted in exchange money has to be a store of value.nobody going to be worthless when they tried to buy goods with it tomorrow.but money is neither the only nor necessarily the best store of value.house value. since money pays no interest and its real purchasing power is eroded by inflation,there are almost certainly better ways to store value .finally money serves as a standard of deferred payment or unit of account ove time.when you borrow,the amount to be reaid next or unit of account over time.then you borrow the amount to be repaid next year is measured in money.uk citizens can get bank loans specifying in dollasr the amount that of exchange.for this,it must act as a store of value as well.and it is usually,though not invariably,convenient to make money the unit of account and standard of deferred payment as well.
1,how many functions does money have?what are they?