Historical Dozen

Date: 03/19/2002 at 23:29:14
From: Vance Wallace
Subject: Why do we ship products in quantities of 12

I have searched the Internet and can not find out why shipping in 12s 
is so common (a case of 12s = 144 is very common). If you could find 
the history of this practice, I would be very thankful for your help.

Date: 03/20/2002 at 07:56:56
From: Doctor Sarah
Subject: Re: Why do we ship products in quantities of 12

Hi Vance - thanks for writing to Dr. Math.

This information about the history of "dozen," from Russ Rowlett's 
_How Many? A Dictionary of Units of Measurement_, may provide a clue:

   http://www.unc.edu/~rowlett/units/dictD.html   

dozen (doz or dz)
a familiar unit of quantity equal to 12. Division into units of 12 
rather than 10 has the advantage that 12 can be evenly divided into 
halves, thirds, or quarters. For this reason, units of 12 have been 
common since the earliest civilizations of the Middle East. "Dozen" 
comes from an old French word dozaine related to the Latin word 
duodecem, "twelve."

- Doctor Sarah, The Math Forum
  http://mathforum.org/dr.math/