C# Basics: Bonus exercises (Calculator)

using System;

namespace Treehouse.bonus
{
  class Program
  {
    static void Main()
    {
      while(true) {

      Console.WriteLine("Enter a number: ");

      var number1 = Console.ReadLine();

      Console.WriteLine("Enter another number: ");

      var number2 = Console.ReadLine();

      Console.WriteLine("Enter an operator (+, -, *, /, or %): ");

      var sign = Console.ReadLine();

      try 
      {
        Double number3 = Double.Parse(number1);

        Double number4 = Double.Parse(number2);

        if(sign == "+")
          {
            Console.WriteLine(number1 + " + " + number2 + " = " (number3 + number4));
          }

        else if(sign == "-")
          {
            Console.WriteLine(number1 + " - " + number2 + " = " (number3 - number4));
          }

        else if(sign == "*")
          {
            Console.WriteLine(number1 + " * " + number2 + " = " (number3 * number4));
          }

        else if(sign == "/")
          {
            Console.WriteLine(number1 + " / " + number2 + " = " (number3 / number4));
          }

        else
          {
            Console.WriteLine("The operator you selected isn't valid... Please try again.");
            continue;
          }

        }

      catch(FormatException)

        {
          Console.WriteLine("One or more of numbers you inputed is invalid. Please try again.");
          continue;
        } 
      }
  }

}
}