Two 2s Make 5

Date: 01/03/2003 at 14:04:39
From: Jen
Subject: A Mathematical Puzzle

I came across a challenge problem to which I cannot seem to find a 
solution. "Using only two 2s and any of the standard mathematical 
symbols, write an expression whose value is equal to exactly five."

Is it a trick question and I can use another number as well as the 
two 2s?

Date: 01/03/2003 at 16:41:36
From: Doctor Peterson
Subject: Re: A Mathematical Puzzle

Hi, Jen.

It took me a while to get this the first time I saw it. You'll need, 
besides the two 2's, a square root, a decimal point, a negative sign, 
and an exponentiation. See what you can do with that!

If you have any further questions, feel free to write back.

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