In economics, currency refers to a commonly accepted medium of exchange. These are usually the coins and banknotes from a particular government, which include the physical aspects of a nation’s money supply. The other part of a nation’s money supply consists of bank deposits (sometimes also add funds), property on which can be transferred by checks, debit cards or other forms of transfer. Deposit money and currency of money in the sense that both are acceptable as payment.
The ruble or ruble (Russian: рубль rubl, plural рубли Rubli, see note on English spelling and Russian plurals with numbers) (code: RUB) is the currency of the Russian Federation and the two partially recognized republics of Abkhazia and South Ossetia. Formerly, the ruble was also the currency of the Russian Empire and the Soviet Union before its separation. Belarus and Transnistria also currencies with the same name. The ruble is 100 kopecks (;: копейка, Kopeyka; plural: копейки, kopéyki Russian sometimes transliterated kopecks or copecks) divided. The ISO 4217 code is RUB or 643; the former code, RUR or 810 refers to the Russian ruble against the 1998 denomination (1 RUB = 1000 RUR).
Currently there is no official symbol  for the ruble, although the abbreviation руб. is widespread. Different symbols presented was  as possible, in part: “РР” (cyrillic for “RR”), an “R” with two horizontal lines across the top (similar to the Philippine peso sign), ₱ a “Р” with a horizontal strike. 
In the 16th Century began the Count Hieronymus Schlick of Bohemia coinage as Joachim thaler (from German thal, or nowadays usually Tal, “valley,” related to “Dale” in English), named for Joachimstal, the valley, where the silver was mined known ( St. Joachim Valley, now Jáchymov, then part of the Holy Roman Empire, now part of the Czech Republic).  Joachimstaler later became the German thaler, a word which eventually found its way into shortened Danish and Swedish as coins, Dutch as Daalder, Ethiopian as ታላሪ (Talari), Hungarian as a larger Italian as Tallero and English as the U.S. dollar.  Alternatively, Thaler said of the German coin Guldengroschen (“great guilder” come from the silver, but equal to the value of a gold guilder), minted from the silver of Joachimsthal.
The U.S. dollar (sign: $; code: USD, also abbreviated U.S. $), also known as the American dollar is the official currency of the United States of America and its overseas territories. It is divided into 100 smaller units called cents or pennies divided.
The dollar is the currency most used in international transactions and is one of the world’s reserve currencies.  Several countries have as their official currency, and in many others it is the de facto currency.  It is also used as the sole currency in some British Overseas Territories (British Virgin Islands and Turks and Caicos).
The Constitution of the United States of America, provided that the Congress of the United States is the power “to mint coins” have.  to implement these laws are currently in force § 5112 of Title 31, United States Code committed. § 5112 requires the forms in which the U.S. dollar must be issued.  These coins are available in Section 5112 as “legal tender” used in payment of debts.  The Sacagawea dollar is an example of the copper alloy dollars. The pure silver dollar is known as the American Silver Eagle. § 5112 also provides for the minting and issuance of other coins, the values ranging from one cent to fifty dollars for.  These are described more fully in other coins Coins of the United States dollar.
All euro coins have one common side and one national. Face is the same for all countries and the value of the coin depicts the background of the card. For coins of 1, 2 and 5 cents a map of Europe, the fifteen countries of the eurozone in its creation are preceded by nausea, compared to the rest of the map. If other coins first map shows only fifteen, but since 2007 has been added to map a large part of Europe, including countries outside the European Union, Norway.
Tails specific to each country and presents an image chosen by the country of issue. In most cases it is a national symbol and a stylized portrait of the reigning monarch. In this way the coins are distinguished by nationality, but are legal tender in all euro area countries, regardless of which side is issued. Currently there are in circulation Coins of 1, 2, 5, 10, 20 and 50 cents and 1 and 2 euros. In order to avoid the use of coins of 1 and 2 cents in Finland by law, in the Netherlands as practices that price in cash are rounded to 5 cents.  This situation and the unwillingness of some stores to accept large bills, was criticized by the European Commission. 
The euro is one of the youngest currencies in the world, appeared officially on January 1, 1999 and came into general use on January 1, 2002 It is the successor of another currency – ECU.
For a single European currency took decades preparation, beginning to accept the Treaty of Rome in 1957, which established the European Economic Community. On economic, monetary and political union are placed with the signing of the Maastricht Treaty in 1992, and with it created and the single European currency. In 1995 the Madrid European Council member states unanimously adopted the name “euro”.