The base-60 notational system for representing Real Numbers. A base-60 number system was used by the Babylonians and is preserved in the modern measurement of time (hours, minutes, and seconds) and Angles (Degrees, Arc Minutes, and Arc Seconds).
See also Base (Number), Binary, Decimal, Hexadecimal, Octal, Quaternary, Scruple, Ternary, Vigesimal
References
Bergamini, D. Mathematics. New York: Time-Life Books, pp. 16-17, 1969.
Weisstein, E. W. ``Bases.'' Mathematica notebook Bases.m.