Integers in Daily Life

Date: 05/31/2002 at 10:29:41
From: Jessica, Tracy, and Mike
Subject: integers 

Hi, 

We want to ask you how integers are used in daily life? 
Thank you.

                                   Sincerely, 
                                   Jessica, Tracy, and Mike

Date: 05/31/2002 at 12:31:33
From: Doctor Peterson
Subject: Re: integers 

Hi, Jessica, Tracy, and Mike!

You just used an integer when you typed your age in! Anytime you 
count anything, you are using integers. That's because integers 
are all the positive and negative whole numbers, _including_ the 
natural numbers you first learned. So you've been using integers 
all your life.

Perhaps you really meant, how are negative numbers used (since 
you were probably introduced to the term "integer" as a way of 
extending the natural numbers to include negative numbers)?

If you live in a cold climate, you use negative numbers (often 
negative integers) to tell the temperature in the winter. That is 
more likely if you live in a country where the Celsius scale is 
used.

If you do any kind of science or engineering, you will find 
negative numbers essential. Even when quantities we measure, like 
mass or pressure, are always positive, we need negative numbers 
to describe changes or differences or rates of change, because 
quantities can both increase and decrease.

Until negative numbers were invented, algebra was extremely 
difficult, so many inventions were held back. Much of the 
technology you take for granted ultimately depends on negative 
numbers!

Money also can increase and decrease, so you need negative 
numbers in finance--though in that world they are only slowly 
catching up with the modern world and learning to write "-10" 
instead of "(10)" or use "red ink" to indicate negative numbers!

You might find these answers interesting:

    http://mathforum.org/library/drmath/view/57152.html
    http://mathforum.org/library/drmath/view/59049.html
    http://mathforum.org/library/drmath/view/52475.html

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