The last digit of 5^n for n>0 has to be 5.

1 = 5^0
5 = 5^1

If 5^k is ...5, that is (10*m)+5, then 
5^k+1
5*5^k
5*(10*m)+5
(10*5*m)+25
(10*2+5*m)+5

Similar proof for the last 2 digits of 5^n for n>1.



----- Original Message -----
From: Ian Gorse <[EMAIL PROTECTED]>
Date: Friday, September 26, 2008 14:14
Subject: Re: [Jprogramming] Difference between 5^100x and x: 5^100
To: Programming forum <[email protected]>

> >
> > As a check, you know that the last digit of 5^n for n>0 has
> > to be 5, so the x:5^100 result can not be the exact result.
> > (The last 2 digits of 5^n for n>1 have to be 25, etc.)
> >
> >
> Thanks for the reply Roger, but I have a very simple question
> regarding the quoted statement.
> 
> Why?
> 
> Please feel free to reply a link or search term if its out of 
> scope of
> this conversation.
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