Sumerian Numerals

Have you ever wondered why hours are divided into sixty minutes, and minutes are divided into sixty seconds? It was all because of ancient Sumeria. The Sumerians used a sexagesimal number system. They had special numerals for one, ten, and sixty, and used a base sixty system, which is what sexagesimal means. They also had words for each of the numbers, just like how we have a numeral for “1” ( 𒁹 ) and the word “one” (aš or diš depending on context). Things get interesting because the numeral for one and sixty looks the same, so you only know which one is in use based on the placement of the character in a string of numbers.



The sexagesimal system is what gives us sixty seconds in a minute and sixty minutes in an hour. It is convenient for fractions, and aside from measuring time is still used to measure angles and geographic coordinates.

While it is unknown exactly why a system based on sixty was chosen, certain numbers were considered sacred by the Sumerians. The number thirty was sacred to the moon god Nanna, which could be the basis of how our months are about thirty days long.

Despite being a sexagesimal system, the Sumerians had names for numbers one through ten (aš or diš, min, eš, limmu, ia, aš, imin, ussu, ilimmu, u), twenty (niš), thirty (ušu), forty (nimin), fifty (ninnu), sixty (giš or geš), six hundred (ge-eš-tu or gešu), one thousand (lim), and three thousand six hundred (šar). Sumerian also had special symbols for certain fractions such as one half, one third, two thirds, and five sixths.

It is nice to know that part of this system lives on and is still used every time we tell the time.