using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("By Erick de la Rosa");

        int option = 0;

        double n1 = 0, n2 = 0;

        while (option < 5)

        {

        Console.WriteLine("\nOperations");

        Console.WriteLine("1) Add \n2) Substrac\n3) Multiplication\n4) Division\n5) Exit");

        option = Convert.ToInt32(Console.ReadLine());

        switch (option)

        {

            case 1:

            Console.WriteLine("enter numbers");

            n1 = Convert.ToDouble(Console.ReadLine());

            n2 = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine("\n{0} + {1} = {2}", n1, n2, n1 + n2);

            break;

            case 2:

            Console.WriteLine("enter numbers");

            n1 = Convert.ToDouble(Console.ReadLine());

            n2 = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine("\n{0} - {1} = {2}", n1, n2, n1 - n2);

            break;

            case 3:

            Console.WriteLine("enter numbers");

            n1 = Convert.ToDouble(Console.ReadLine());

            n2 = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine("\n{0} x {1} = {2}", n1, n2, n1 * n2);

            break;

            case 4:

            Console.WriteLine("enter numbers");

            n1 = Convert.ToDouble(Console.ReadLine());

            n2 = Convert.ToDouble(Console.ReadLine());

            Console.WriteLine("\n{0} / {1} = {2}", n1, n2, n1 / n2);

            break;  

        }

            Console.ReadLine();

        }

    } 

}