Duodecimal, << `doo` uh DEHS uh muhl, >> system is a way of grouping numbers based on 12 instead of 10, as in the commonly used decimal system. The word duodecimal comes from the Latin words for two and ten. The system uses 12 symbols, which are 0 through 9 and two additional symbols, such as A and B, for the decimal numbers 10 and 11. The decimal number 12 is written as 10 in duodecimal. 1A stands for 22 (12 + 10). Merchants use a duodecimal system when they count by the dozen or gross (12 dozen or 144). Early people may have chosen 12 as a unit of measure, such as 12 inches to a foot, because it can be evenly divided by more numbers than 10 can.
