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Calculators and e+


Date: 09/27/98 at 21:21:22
From: Melissa
Subject: Calculators

For my math class I was given the assignment to find out what "e+" 
means on the calculator.


Date: 09/29/98 at 08:57:39
From: Doctor Peterson
Subject: Re: Calculators

Hi, Melissa. I tried using Help in the calculator on my computer and 
was disappointed that they don't explain the "e". Probably the manual 
for a scientific calculator would explain it.

The e stands for Exponent, which means the number of tens you multiply 
a number by. 

For example, if I square 123456789, I get 1.524157875019e+16, which 
means that the answer is 1.524157875019 times 10 raised to the 
sixteenth power (that is, multiplied by 10 sixteen times). To write it 
as a regular number, you can just move the decimal point to the right 
sixteen places, since multiplying by ten moves the decimal point one 
place to the right:

   1.524157875019e+16 = 15,241,578,750,190,000

That's over 15 quadrillion.

You can also have a negative exponent, which means you have to move 
the decimal point to the left. For example, if I divide 1 by 
123456789, I get:

   8.10000007371e-9 = 0.00000000810000007371

In both cases, you can see that the reason for using the "e" notation 
is to be able to show a number that would have too many digits to 
display if they wrote it all out.

If you are interested in more about this, you might do a search in the 
Dr. Math archives for the words   scientific notation .

- Doctor Peterson, The Math Forum
  http://mathforum.org/dr.math/   
    
Associated Topics:
Elementary Large Numbers
Elementary Number Sense/About Numbers
Elementary Square Roots
Middle School Exponents
Middle School Number Sense/About Numbers

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