using System;

using System.Globalization;

public class Program

{

    public static void Main()

    {

        var result =  ((decimal)0.07) + (GetAsDecimal("125.37988897726417777777777778") * ((decimal)0.13 / ((decimal)0.8)));

        Console.WriteLine(result);

        result =  ((decimal)0.07) + (GetAsDecimal("flute") * ((decimal)0.13 / ((decimal)0.8)));

        Console.WriteLine(result);      

        result =  ((decimal)0.07) + (GetAsDecimal("1,2") * ((decimal)0.13 / ((decimal)0.8)));

        Console.WriteLine(result);              

    }

    public static decimal GetAsDecimal(string nb)

    {

            try

            {

                decimal val = 0;

​

                val = Convert.ToDecimal(nb, CultureInfo.InvariantCulture);

                return val;

            }

            catch (System.Exception)

            {

                return 0;

            }       

    }

}