Five from Twenty-five

Date: 07/22/97 at 16:56:05
From: Chris
Subject: Division

How many times can you take 5 away from 25?

Chris!

Date: 07/28/97 at 10:27:01
From: Doctor Rob
Subject: Re: Division

Answer 1:

You can take 5 away from 25 as many times as you like, but you will
always get an answer of 20:

   25 - 5 = 20
   25 - 5 = 20
   25 - 5 = 20
   ...

Answer 2:
You can take 5 away from 25 as many times as you like:
  25 - 5 - 5 - ... - 5 = ??.
If the number of 5's is more that 5, the answer will be negative.

Answer 3:
You can only take 5 away from 25 once.  That leaves you with 2, from
which you can't take a 5 away.

Or, if what you want to do is to keep subtracting 5 from 25 until you 
get to 0:

    25 - 5 = 20
    20 - 5 = 15
    15 - 5 = 10
    10 - 5 =  5
     5 - 5 =  0

That's 5 subtractions, which shows you that there are five 5's in 25 
and that 25 divided by 5 is 5.

-Doctors Rob and Sarah,  The Math Forum
 Check out our web site!  http://mathforum.org/dr.math/