I was thinking % was the way to go as well. Maybe something like this?

Code:
            int x = 2;
            int y = 3;

            for (int i = 1; i <= 100; i++)
            {
                if ((i % x == 0) && (i % y == 0))
                {
                    Debug.WriteLine(i.ToString() + " is divisible by " + x.ToString() + " and " + y.ToString());
                }
                else if (i % x == 0)
                {
                    Debug.WriteLine(i.ToString() + " is divisble by " + x.ToString());
                }
                else if (i % y == 0)
                {
                    Debug.WriteLine(i.ToString() + " is divisible by " + y.ToString());
                }
            }