Origin of the Percent Symbol

Date: 02/12/2002 at 21:09:18
From: Travis Beaton
Subject: Percent symbol

Where did the percent symbol originate? My teacher thinks it was 
from the sign for the number 100 with two zeros on each side of the 
1, but I am not sure.

Date: 02/12/2002 at 23:34:53
From: Doctor Peterson
Subject: Re: Percent symbol

Hi, Travis.

According to D. E. Smith, _History of Mathematics_, the sign 
originated in 15th-century manuscripts as

         o        o
    per c  or  p c

for "per cento" or "per hundred." By the mid-17th century it was

         o
    per ---
         o

and later the "per" was dropped. Later it was tilted into what Smith 
calls the "solidus form, %", since "/" is called a solidus.

I seem to recall somewhere reading that it was originally "numero per 
cento" in Italian, which was written as

     o /
    n / c

using the solidus for "per," as in a fraction; the c closed up to form 
a second o, while the n disappeared. I can't think what book that 
could be from, if not from Smith; but Smith apparently doesn't agree. 
So this may just be a figment of my imagination.

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