Dividing by a Negative Fraction

Date: 01/24/2002 at 21:08:27
From: Krys
Subject: Dividing fractions

I understand how to divide fractions, but what if one of them is 
negative? What do I do?

Date: 01/24/2002 at 23:23:08
From: Doctor Peterson
Subject: Re: Dividing fractions

Hi, Krys.

Whenever you divide or multiply any kind of signed numbers, you can do 
it in two steps. First do the multiplication or division, ignoring the 
signs. Then look at the signs, and follow the rule: if the two signs 
are the same, the sign of the result is positive, otherwise it's 
negative.

For example, 3/4 divided by -1/2:

Numbers:

    3/4 / 1/2 = 3/4 * 2/1 = 3/2 = 1 1/2

Signs:

    + / - = -

So the quotient is -1 1/2.

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