who does G-20 represent?

meaning of g20
intro: now in the news we hear about Trump at the G20 meeting. who does g20 represent? what about g3-10?
the g is simply "group" meaning gathering representatives of countries for economic purposes. these groups are not the "same lists" with additions except g20 which is the seven of g7 with 13 more representatives.
g20 includes one representative for the european-union with the g7 (as below): britin, canada, france, germany, italy, japan, and u.s. (they meet called g7 as below) plus 12 more countries. the 12 are Argentina, Australia, Brazil, China, India, Indonesia, Mexico, Russia, Saudi Arabia, South Africa, South Korea, and Turkey. note: both germany already represented and others lacking their own representative.
in abc order Group Twenty (representing the European Union and 19 countries: Argentina, Australia, Brazil, Canada, China, France, Germany, India, Indonesia, Italy, Japan, Mexico, Russia, Saudi Arabia, South Africa, Republic of Korea (south), Turkey, United Kingdom, and United States. Some of these are members in G-7).
G1 or 2? as a group there must not be g1 alone. if Trump meets chinese leader that is like G2 but hardly a "group" either.
g3 trade group representing: Columbia, Mexico, Venezuela.
g4 Group Four (4 countries: Brazil, Germany, India, and Japan which want to join the United Nations Security Council.).
g5 five economic powers: France, Germany, Japan, UK, US.
g6, year 1975 represented 6 countries that are economic powers (not the 6 strongest economies)
France, Germany, Italy, Japan, UK and US.
g7 year 1976 added canada to that group so bcfgiju
g8 added russia in 1997 until year 2013 they rejected russia claiming ukraine situation was bad so ignore its needs so g8 change to g7 as above. russia is only included in g20 as above.
g9 from 1965-1968 for cooperation during the cold war. It represented: Austria, Belgium, Bulgaria, Denmark, Finland, Hungary, Romania, Sweden, Yugoslavia.
g10 The Group of Ten represents the U.S. and ten industrialized countries (Belgium, Britain, Canada, France, Germany, Italy, Japan, the Netherlands, Sweden, Switzerland) for trade cooperation.
please fix on page
http://econmentor.com/index-hs/g---h/g3-g5-g8-countries/text/1304.html
g5 not the leaders because most behind china, not listed. so please delete "leading" also
g8 not "biggest" and  since 2013 they rejected russia  so please fix "G8 consisted of eight powerful economies." and mention the change to become G-7.