Thread: Find all naturAls numbers. X , Y..

1. Find all naturAls numbers. X , Y..

A is in decimal representation :
Find all naturAls numbers. X , Y.. so that A divide by 25 .

2. 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 $y=\{2,7\}$
$x=\{0,1,2,3,4,5,6,7,8,9\}$

3. 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}
$x=\mathbb{N}$