using System;

public class Program

{

    public static void Main()

    {

        string str = "9";

        Console.WriteLine("Is {0} numeric : " + str.IsNumeric(), str);

    }

}

public static class ExtensionMethods

{

    public static bool IsNumeric(this string s)

    {

        float output;

        return float.TryParse(s, out output);

    }

}