using System;

public class Program

{

    public static void Main()

    {

        int sum = 0;

        int number = 1;   

        int n = 250;

        // Sum the first n numbers starting at 1.

        while (number <= n)                                   

        {                                                                 

            // Console.WriteLine(number);

            sum += number;

            number++;                                               

        }

        Console.WriteLine("the sum of the first {0} numbers is: {1}", n, sum);

        Console.WriteLine("Number is at " + number);

        int check = n/2*(n+1);

        Console.WriteLine("Gauss formula result is " + check);                                             

        }    

    }

​