currency
The monetary system of a particular country is referred to as currency.
For example, the currency of the United Kingdon is the pound (£), and the currency of the United States of America is the dollar ($).
Steffan is going on holiday to Spain. The country’s currency is the euro (€). The exchange rate is £1 = €1.14, and Steffan wants to exchange £400.
Therefore, 400 × 1.14 = €456
This means that Steffan has €456 to spend on his holidays.