Don't Use Calculators

Date: 12/18/2000 at 18:09:30
From: donnamorris
Subject: Why should you not use calculators to do math? 

Why should children not use calculators to do math? Please state 
several reasons. 

Thank you. 
Ms. Morris

Date: 12/18/2000 at 18:49:16
From: Doctor Ian
Subject: Re: Why should you not use calculators to do math? 

Hi Ms. Morris,

It might be going a little too far to say that children "should not 
use calculators" to do math. There are times when a calculator is just 
the ticket - for example, when you want an approximate value for the 
cube root of 59.  

What children shouldn't do is _depend_ on calculators to do simple
calculations, like multiplying integers from 1 to 10, or adding and
subtracting numbers, or dividing numbers with relatively few digits.  

(I wouldn't hesitate to whip out a calculator to compute something 
like 2944521.324562 divided by 192.87465, although I might just divide 
3 million by 200 and call it close enough for government work.)

Some reasons children shouldn't depend on calculators include:

1. There won't always be a calculator around when you need one; or if
   there is one, the battery may be dead.  

2. It's about a zillion times quicker to use your brain to figure out
   that 7 x 6 = 42 than it is to key it into a calculator. This 
   doesn't make much difference if you just want to do one 
   calculation, but when you're simplifying algebraic expressions you 
   typically do dozens, even hundreds of simple calculations, which  
   makes relying on a calculator sort of like trying to run a marathon 
   and having to stop every twenty feet to re-tie your shoes.   

3. Calculators only use decimal approximations to real numbers, which 
   gives an unrealistic idea of how the real number system works, and 
   obliterates any opportunity to develop an appreciation for the 
   crucial difference between an exact answer and an approximate one. 

4. Children who depend on calculators without developing an 
   independent number sense are unable to tell when they've arrived 
   at ridiculous answers because they've inadvertently typed in the 
   wrong number, or have missed a decimal point, or made some similar  
   error. So they can be computing the speed of a train, get an 
   answer like '394312353.31395 miles per hour', and have no choice 
   but to assume that it must be right, because it's 'what the 
   calculator said'.  

5. Learning to get along without a calculator is an excellent object 
   lesson in growing up. The essence of becoming an adult is learning 
   to put up with a little pain up front in order to avoid a lot of 
   pain later on. Children who avoid the pain of learning their basic 
   arithmetic facts by depending on calculators are setting themselves 
   up for enormous amounts of pain and frustration later in life.  

I hope this helps. Write back if you'd like to talk about this some 
more, or if you have any other questions. 

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