# Re: Too narrowly defined: DIVISION SIGN & COLON

From: Mark E. Shoulson <mark_at_kli.org>
Date: Tue, 10 Jul 2012 21:22:36 -0400

On 07/10/2012 03:30 PM, Asmus Freytag wrote:
> On 7/10/2012 3:50 AM, Leif Halvard Silli wrote:
>> Asmus Freytag, Mon, 09 Jul 2012 19:32:47 -0700:
>>> The European use (this is not limited to Scandinavia)
>> Thanks. It seems to me that that this tradition is not without a link
>> to the (also) European tradition of *not* using the DIVISION SIGN (÷)
>> for division.
>
> Is it _ever_ used for division? I'm curious, right now I can't recall
> ever having seen an example.

Yeah, I've hardly ever seen it used that way. Here's what I think is
going on, and I present these "facts" of the history of the symbol
without the tiniest shred of evidence:

Mathematicians have been using / and, even more pervasively, full
displayed fractions (with a numerator actually on top of a denominator
with a line in-between) for division for some time now. The + and -
symbols are also well-entrenched. When people started making
calculators, and maybe even before, if there were some situations where
it made sense to be talking about the operators separately, I guess "/"
wasn't looked upon very favorably as a symbol for division, maybe for
aesthetic reasons, or confusability or whatever, or maybe because the
"real" division symbol is "writing this on top of that with a line
between." So when it came time to assign a symbol to division that
could be used on calculator keys or such settings, someone made up a
symbol for "this atop that with a line": we'll put the line, and then a
dot on the top and bottom showing where stuff is supposed to go. I'm
certain (again, no evidence presented, I'm making this up, but I think
I'm right) that the origin of ÷ is from a displayed fraction with dots
to show "put things here and there." Which is why it's so rarely used,
because it never really was used, it just came into existence to put on
calculator keys.

I'd not heard of using it as a subtraction symbol before, but it feels
to me like someone thought that the normal minus sign was too confusable
with an ordinary hyphen or something, maybe in a mixed presentation with
ordinary text and mathematical signs and negative numbers mixed
together, and was looking for something hyphen-looking but distinctive,
and used the ÷ since it looks hyphen-y and nobody seriously uses it for
division. (I think it would have been better if someone started a
convention of, say, drawing the minus sign with an up-pointing serif on
the left and a down-pointing serif on the right, or some such
distinctiveness, and then that would be a glyph variant for the MINUS
SIGN). Good evidence *against* this theory might be demonstrating usage
of ÷ for subtraction a long time ago.

It sounds to me like this is a case of a somewhat unusual use of a
character; I might say "non-standard" but it's really more "according to
a different standard than what I might have expected." This is still
the same ÷ character, just that some people use it to mean subtraction
instead of division. It isn't a new character.
Received on Tue Jul 10 2012 - 20:23:31 CDT

This archive was generated by hypermail 2.2.0 : Tue Jul 10 2012 - 20:23:31 CDT