U.S. dollars generally refer to U.S. dollars.

The United States dollar (United States dollar currency abbreviation: USD; ISO 4217 currency code: USD; symbol: USA$) is the currency of the United States of America, the Republic of El Salvador, the Republic of Panama, the Republic of Ecuador, and the Democratic Republic of East Timor*

The legal tender of the Republic of **, the Republic of the Marshall Islands, the Federated States of Micronesia, the Republic of Kiribati and the Republic of Palau.

The U.S. dollar banknotes in circulation are all versions of banknotes issued since 1929.

Appeared after the passage of the United States Coinage Act of 1792.

The current issuance of U.S. dollars is controlled by the U.S. Federal Reserve System.

Since 1913, the United States has established the Federal Reserve System and issued Federal Reserve Notes.

More than 99% of current banknotes in circulation are Federal Reserve notes.

The authority responsible for issuing U.S. dollars is Congress, and the specific issuance business is handled by the Federal Reserve Bank.

After World War II, continental European countries reached an agreement with the United States and agreed to use U.S. dollars for international payments. Since then, the U.S. dollar has been widely used as a reserve currency in countries other than the United States and eventually became an international currency.

The sign "$" is a representative symbol of the dollar sign.

The origin of "$" can be traced back to the early 16th century, when Spain minted a silver dollar called "PESO" (peso).

The pattern of this silver coin has a crown and royal emblem (lion and castle) on one side and two pillars on the other side.

According to Western mythology, they are the pillars of Hercules and represent the peaks on both sides of the Strait of Gibraltar.

According to legend, a long time ago, Europe and Africa were connected to each other, but were later pulled apart by the strongman Hercules.

In 1732, Mexico City used a machine to cast a "double-column silver dollar" with a pattern similar to that of "PESO".

Just add the pattern of the east and west hemispheres between the two columns, and there is a curved "$$" shape on each column.

Over time, people began to regard "$" as the symbol of silver dollars.

Today, there are still many countries in the world that use "$" as their national currency symbol. Therefore, sometimes to distinguish the currencies of these countries (regions) (including the United States), the country (region) is added before "$".

), such as US dollar (USA$), Canadian dollar (CAN$), Hong Kong dollar (HK$).

You can write "$" directly if there is no ambiguity.

There are many theories about the origin of this dollar sign, two of which are more common.

One theory is that this symbol is formed by placing a narrower U on a wider S, so it represents the dollar sign of the United States.

Another theory points out that it is the evolution of PS superimposed writing.

PS is the abbreviation of Pesos, a round coin in the United States from the 18th to the 19th century. This coin was used nationwide until the United States officially established the mint in 1974.

Later, the U.S. government recognized the $ symbol as a unit of the new currency, the dollar.

When writing, $ should be placed in front of the number.

For example, 1 U.S. dollar should be written as $1, and 50 U.S. dollars should be written as $50.