A number system using the powers of
12, which are allotted place values as in
the decimal system. The number written in
decimals 4092 can be expressed as (2 × 123) + (4 ×
122) + (5 × 121) + (0 × 120)
or, in duodecimals, 2450. Fractions are expressed similarly. Two extra symbols
are needed for this system to represent the numbers 10 and 11; these are
generally accepted as X (dek) and Σ (el) respectively.
|In 1944 the Duodecimal Society, advocating the use
of the duodecimal for scientific purposes, was formed in New York.
Although the society still exists, its name has changed to the Dozenal
Society of America and the Dozenal Society of Great Britain. The word
"dozenal" is used instead of "duodecimal" because the latter comes
from Latin roots that express twelve in base-ten terminology.
The advantage of this system can be realized by consideration of the integral
factors of 10 and 12: 10 has two (2, 5) while
12 has four (2, 3, 4, 6). The fractions one-third and two-thirds are 0.4
and 0.8, respectively, in duodecimal – much simpler than the recurring
expressions 0.3333... and 0.6666... in the decimal system.
The most common examples of everyday use of this system are the setting
of 12 inches to the foot and 12 months to