using System;

using System.Globalization;

public class Program

{

    static decimal NotationToNumber(string notation)

        {

            return Decimal.Parse(notation, NumberStyles.Float);

        }

​

        static string NumberToNotation(double number)

        {

           return string.Format("{0:E6}", number);

        }

    public static void Main()

    {

        Console.WriteLine("Number value: 2,                Notation: "+ NumberToNotation(2));

        Console.WriteLine("Number value: 4,321.768,        Notation: " + NumberToNotation(4321.768));

        Console.WriteLine("Number value: −53,000,          Notation: " + NumberToNotation(-53000));

        Console.WriteLine("Number value: 6,720,000,000,    Notation: " + NumberToNotation(6720000000));

        Console.WriteLine("Number value: 0.000 000 007 51, Notation: " + NumberToNotation(0.00000000751));

​

        Console.WriteLine("\n");

​

        Console.WriteLine("Notation: 2.00E+000             Number value: " + NotationToNumber("2.00E+000"));

        Console.WriteLine("Notation: 4.32E+003             Number value: " + NotationToNumber("4.321768E+003"));

        Console.WriteLine("Notation: -5.30E+004            Number value: " + NotationToNumber("-5.30E+004"));

        Console.WriteLine("Notation: 6.72E+009             Number value: " + NotationToNumber("6.72E+009"));

        Console.WriteLine("Notation: 7.51E-009             Number value: " + NotationToNumber("7.51E-009"));

    }

}