# Find all naturAls numbers. X , Y..

• Aug 4th 2009, 09:32 AM
dhiab
Find all naturAls numbers. X , Y..
A is in decimal representation : http://www.mathramz.com/xyz/latexren...d6b4f14a65.png
Find all naturAls numbers. X , Y.. so that A divide by 25 .(Rofl)
• Aug 4th 2009, 09:45 AM
Gamma
Maybe I am misunderstanding something, I don't know.

so your number can be written:
$A=100\cdot xyxyxyxyx + y5$
where these are the decimal representation.

$25|100$, so you need only worry about when $25|y5$ which is clearly only 25 or 75.

so $y=\{2,7\}$
$x=\{0,1,2,3,4,5,6,7,8,9\}$
• Aug 4th 2009, 09:49 AM
Gamma
further reflection
unless x and y can represent multiple digit numbers?
Then $y=\{n\in \mathbb{N}|n$ ends in a 2 or a 7}
$x=\mathbb{N}$