The Babylonians, who lived in Mesopotamia (3500BC), have one of the oldest known number systems known of all time. The mathematicians, astronomers and early renaissance men Nabu-rimanni and Kidinu are said to have created Babylonian number system.
The Mayans, who thrived in current day Mexico(2000BC-200AD) acquired and combined preceding numerical systems to create the base 20 numerical system used in regular Mayan culture and script. The system is used in the Mayan calendar, which we created our current day calendar with.
The roman numerical system, which is used often in modern society for uses such as marking clocks, naming sporting events, and legal document marking, uses different arrangements of I,V, and X to represent different values. I represents 1, V represents 5, and X represents 10. Other letters are used to represent larger numbers. The base 10 system was derived by various Romans from the Etruscan numeral system.
Note: When writing roman numerals, to reach numbers that are not directly listed as letters you have to put other numbers in front or behind each other to add or subtract to get the number desired. For example, the number 7, while not listed as a letter, can be written as VII because 5+1+1=7
The Greek Numeral System uses their alphabet system to make their number system. The system is based on the base 10 system. Base 10 is the number system we use. The units 1-9 are represented with Greek letters. These letters range from Alpha to Theta, which we use in our math system commonly. (ie. Theta to show degree measures etc.). Also chemists use alpha beta and gama to name different particles
Fun Fact!
Frats use Greek numerals such as alpha and beta to represent and name themselves