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In Duodenary arithmetic the base is 12, just as in ordinary decimal arithmetic the base is 10 ; e.g. in the former, 257*81 stands for 2 x 122 + 5 x 12 + 7 + 8/12 + â–¡(1/12) ; just as in the latter it stands for 2 x 102 + 5 x 10 + 7 + 8/12+1/(10 ) . Practically, a partial use of the system is made in Duodecimals where the subdivisions of the foot are reckoned by twelfths : 1 foot = 12 primes, 1 prime = 12 seconds, etc.

n. pl. A multiplication by twelves, as of feet and inches, employed by artificers in computing the superficial and solid contents of their work.