The Why of Algebra

Date: 11/13/98 at 08:33:58
From: brittney smith
Subject: Algebra

I don't get the point of algebra. What is algebra for, when we have 
multiplication and division?

Date: 11/13/98 at 11:53:27
From: Doctor Rick
Subject: Re: Algebra

Hi, Brittney. 

Don't let your loyalty to your old friends multiplication and division 
keep you from making friends with algebra. Algebra doesn't replace them 
at all.

What algebra does is to help you decide when to multiply and divide. 
It is a problem-solving tool.

The basic trick that makes algebra work is this. Say there's some 
quantity, like a weight or an amount of money, that you don't know. The 
fact is, even though you don't know the exact number, you know a great 
deal about it just because you know it's a number. So you give it a 
name (a variable) and you treat it just as if it were a number that you 
know. By applying certain rules that work for all numbers, you can 
figure out what the number must be.

Algebra is a toolbox full of tools that help you take a problem apart 
and put it back together. Multiplication might be the screwdriver, but 
your algebra toolbox also has clamps that hold the pieces so the screw 
will go in the right place.

Algebra is also a language that lets you talk about a problem, and 
think about it. When I try to help a pre-algebra student solve a word 
problem, it's hard, because I don't know what words to use to explain 
how I thought about the problem. But if I can use algebra, I just have 
to define some variables and write an equation, and explain which rules 
to use to change the equation until you get the answer.

Those are just a few thoughts on what algebra is good for. Don't sell 
it short. Algebra will be a good friend to have some day when you're 
wondering, "Should I add first, or multiply?"

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