A four digit number is squared to form an eight digit number. The center four digits of that square form the four digit number. Find all possible four digit numbers.

(If 'abcd' was the four digit number, then the eight digit number would look like 'wxabcdyz'.)

(In reply to re: Excel Solution by Sandeep)

I did it with Excel too but did not post as others have posted. Here's how I did it:

Column A: Listed 3163 to 9999
Column B: Square of Column A
Column C: Used rounddown function to round down B/1000000
     That gets the very first two digits (wx in this case)
Column D: Column B minus 1000000 times Column C
     This gets rid of the first two digits
Column E: Round down column D divided by 100
     This gets rid of the last two digits
Column F: Column A minus Column E
Column G: Copy Column F, Paste the values using paste special
     This is important since you cannot look for the 0 with any
     function if it's filled with a formula

Last Step: Use the find cell under Edit to find a cell with a value of 0.

Posted by np_rt on 2004-11-28 18:35:05