What is the Number?

Date: 29 Mar 1995 10:05:01 -0500
From: JOSEPH CAPASSO
Subject: help

I'm in 7th grade, need someone to explain how to solve 
this simple word problem.

"You know that a certain 5-digit number is a power of 7 
and that its ones digit also is 7.  What is the number?"

If you can help me, I have a couple more....

                      Thanks
                          Joe

Date: 29 Mar 1995 13:27:31 -0500
From: Dr. Ken
Subject: Re: help

Hello there!

Well, I think that the easiest way to solve this problem is 
probably to start writing down the powers of 7: 7, 49, 343, 
etc.  How many of them have five digits?  It may take a 
minute or two to write them down, but once you do that, it 
will become pretty clear what the answer is.  

Write back if you need more help!

-Ken "Dr." Math