The US dollar (English: United States dollar, ISO 42 17 code: USD), also known as the US dollar, is the official currency of the United States.

Its appearance is due to the passage of the coin bill of 1792. It is also widely used as a reserve currency outside the United States. At present, the issuance of US dollars is controlled by the Federal Reserve system. The most commonly used symbol for the dollar is "$", while the symbol for the cent is "?" . The ISO 42 17 standard adopted by the International Organization for Standardization is USD.

$ is the abbreviation of the dollar, commonly known as the dollar, and is the currency of the United States. The currency symbol is the dollar. At present, the US dollar bills in circulation are various versions of bills issued since 1929, mainly Federal Reserve bonds. The denominations of banknotes are 1, 5 10, 20 and 100 yuan, and the denominations of coins are 1, 5 10 and 25 cents.

The monetary units in the United States are: US dollar ($), US cent () and rounding: $1=100;

Paper money $ 1, $5, $ 10, $20, $ 100.

Coin 1%, 5%, 10%, 25%

The competent department for issuing US dollars is Congress, and the Federal Reserve Bank is responsible for the specific issuance business. The dollar is the basic currency in foreign exchange, the main currency in international payment and foreign exchange transactions, and occupies a very important position in the international foreign exchange market.