using System;

​

public class MyProgram

{

    public static void Main(String[] args)

    {

        int result1;

        result1 = 1 + 2 + 3 + 4;

        int result2;

        result2 = 4321;

        int result3;

        result3 = 4123;

        int result4;

        result4 = 1324;

        Console.WriteLine("The sum of the digits is " + result1);

        Console.WriteLine("The numbers in reversed order: " + result2);

        Console.WriteLine("The last digit in the first position: " + 4123);

        Console.WriteLine("Exchange the second and the third digits: " + 1324);

    }

}

​