Base 12 Numbering system

• Twelve was used as a basic group of things. The group of twelve was then multiplied by other numbers to get bigger numbers. One example being the Great Hundred of Northern Europe which was 120 units (10 x 12). The group of twelve could also be divided into equal groups by many numbers due to its many factors (numbers that can be divided into a number without a remainder). The Roman Duodecimal fractions consisted in fractions of only those factors of 12. (twelfths, sixths, fourths, thirds and halves).

• Base 12 was used not as a formalized place value, but rather as a grouping value that combined with other values to a larger grouping value. For example 10 twelves are 120 or the Great Hundred. The Cycle of Cathay for China represents the combination of a cycle of 10 and a cycle of 12 which results in a cycle of 120.   Also 5 twelves are 60 which was a highly developed numbering system thousands of years ago. see base 60

• The use of 12 as a grouping value can be seen as arising from its many divisors, which would let someone who had 1 dozen or group of something to divide it up easily.   The use of 12 as a grouping value may also be related to the observation that there are approximately 12 months (moons)  in year.  Many cultures observed 12 zodiacal formations in the stars as the year progressed.

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Last update on 01/26/98

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