Re: [MATHEDCC] signed numbers

John M. Flanigan (johnf@HAWAII.EDU)
Tue, 9 Nov 1999 07:36:57 -1000

Cute example. One could also modify it to refer to points given to
students. I have tried to do it with football yardage gains and penalties,
although it is much more strained.

These examples show our cleverness at inventing unlikely scenerios for
extending the application of integer arithmetic to the multiplication of
negative numbers. The original question remains: is there any "real world"
(of whichever kind) problem for which that operation is really useful?

John M. Flanigan <johnf@hawaii.edu> The equation is the final arbiter.
Assistant Professor, Mathematics --Werner Heisenberg
Kapi'olani Community College The scoreboard is the final arbiter.
4303 Diamond Head Road --Bill Walton
Honolulu HI 96816 History is the final arbiter.
(808) 734-9371 --Edward Gibbon

On Tue, 9 Nov 1999, Al Roy wrote:

> Hi ,
> I read an example about multiplying signed numbers a long time ago. I
> beleive it went like this.
>
> There was an old mailman who had not missed a day of work in thirty years.
> He had worked the same route and knew where to deliver the mail eventhough
> most houses on his route had no addresses. One day he called in sick and
> was replaced by a new mail carrier. The replacement delivered letters to
> the wrong houses due to the lack of addresses.
>
> The next day the veteran mailman returned to work and corrected the errors
> made by the substitute. As luck would have it only checks and bills for
> three dollars had been delivered by the substitute. A check is a +. A bill
> is a -. The veteran mailman either gave a letter that should have been
> delivered but was not + or he took a letter that was delivered but should
> not have been -.
> At the first house he gave two checks of three dollars each that should
> have been delivered there but were not. That household gained six
> dollars(+6).
> At the second house he took two checks of three dollars each that had been
> delivered there by mistake. That household loss six dollars(-6).
> At the third house he gave two bills of three dollars each that should have
> been delivered there but were not. That household loss six dollars.(-6).
> At the fourth house he took two bills of three dollars each that had been
> delivered there by mistake. That household gained six dollars(+6).
> Keep the Faith
> ****************************************************************************
> **************
> ****************************************************************************
> ***************
> Al Roy "We shall not cease from exploration
> Bristol Comm. Coll. And the end of our exploration
> Fall River, MA 02720 Will be to arrive where we started
> 508-678-2811 x2246 And know the place for the first time." Eliot
> ****************************************************************************
> * To post to the list: email mathedcc@archives.math.utk.edu *
> * To unsubscribe, send mail to: majordomo@archives.math.utk.edu *
> * In the mail message, enter ONLY the words: unsubscribe mathedcc *
> * Words in the Subject: line are NOT processed! *
> * Archives at http://archives.math.utk.edu/hypermail/mathedcc/ *
> ****************************************************************************
>

****************************************************************************
* To post to the list: email mathedcc@archives.math.utk.edu *
* To unsubscribe, send mail to: majordomo@archives.math.utk.edu *
* In the mail message, enter ONLY the words: unsubscribe mathedcc *
* Words in the Subject: line are NOT processed! *
* Archives at http://archives.math.utk.edu/hypermail/mathedcc/ *
****************************************************************************