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Dozenal Society of America
Promoting base twelve and alternative base mathematics
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The Dozenal Society of America
The DSA is a voluntary, nonprofit education corporation, organized for the conduct of research and education of the public in the use of dozenal (also called duodecimal or base-twelve) in calculations, mathematics, weights and measures, and other branches of pure and applied science.

The Duodecimal Bulletin

◀️ Issue: Whole Number 91z (109d) | Vol. 46z (54d) No. 2 | Year 11B1z (2005d) ▶️



Click to view PDF

Editor: Prof. Jay Schiffman

Associate Editor: Prof. Gene Zirkel

Contents:

  • President’s Message | Jay Schiffman
  • Reprint: The Do-Re-Mi System of Dozenal Nomenclature: A Trip into the Land of Ever-Ever | Henry Clarence Churchman
  • Another Arithmocrypt | Mary Lloyd
  • Reprint: Aspirant’s Test Number 1
  • Our New Treasurer: Prof. Ellen Trufano, St. John's Univ., Jamaica NY
  • Dozenal Terminology | Ursula Leubner
    • ten, eleven, dozen, gross, cube
  • Announcement of Annual Meeting — 11B1z (2005d)
  • New Web Dozenal Forum: DozensOnline | DSGB (Brian Parry, Robert Carnaghan, Brian Bishop, Shaun Ferguson)
  • Answers to Aspirant’s Test Number 1
  • Jottings
    • Richard Trelfa passed away
    • Ian Patten passed away
    • Ad Multos AnnosL Skip Scifres
  • Arithmocrypt Solution
  • Mail Bag
    • Paul J. M. Sweet | enjoyed Dr. Robert C. Gilles’ article “Let’s Not Go Metric”
    • Robert Carnaghan | DSGB response
    • Jean Kelly | interesting dictionary entry for “duodecimal” on the web
  • New Board Members: John Earnest (VP), Ellen Trufano (Treasurer)
  • Why Change?
Copyright © 11B9–120Az (2013–2026d). The Dozenal Society of America. Contact Us.
Creative Commons License
This site and the documents on it are licensed under a Creative Commons Attribution 4.0 International License.

This site expresses numbers in alternative bases, particularly dozenal (also called duodecimal, or base twelve).
The DSA does not endorse any particular notation or pronunciation scheme for alternative bases.
However this site defaults to the following to ensure online readability across all platforms:
“Computerese” uppercase letters represent transdecimal digits: A = ten, B = eleven, C = twelve, etc.
Single-character subscripts annotate bases: d = decimal, z = dozenal, x = hexadecimal, etc., e.g., 2014d = 11BAz = 7DEx.

(0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 ...)d
(0 1 2 3 4 5 6 7 8 9  A  B 10 11 12 13 14 15 16 17 18 19 1A 1B 20 21 22 23 24 25 26 27 28 29 2A 2B 30 ...)z
(0 1 2 3 4 5 6 7 8 9  A  B  C  D  E  F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F 20 21 22 23 24 ...)x

PDF documents on this site reflect changing practices among dozenalists over the years:
Various symbols have been used to represent digits ten and eleven:
Dwiggins 𝒳 and Ɛ (often rendered X and E); Bell Telephone * and #; Pitman turned 2 and 3 (↊ and ↋); etc.
Italics were once used to distinguish dozenal numbers from decimal: e.g. 0.5 = 0.6.
Later, semicolon became a separate‑identity “dozenal point”, versus period as “decimal point”: e.g., 0.5 = 0;6.
However, subscript base annotations provide a more versatile solution that is least‑change: e.g., 0.5d = 0.6z = 0.8x

Dozenal offers superior divisibility over decimal, which can make everyday arithmetic easier to learn:
⅙ = 0.2z | ¼ = 0.3z | ⅓ = 0.4z | ½ = 0.6z | ⅔ = 0.8z | ¾ = 0.9z | ⅚ = 0.Az
⅙ = 0.1666…d | ¼ = 0.25d | ⅓ = 0.333…d | ½ = 0.5d | ⅔ = 0.666…d | ¾ = 0.75d | ⅚ = 0.8333…d

EACH ONE, TEACH ONE.