using System;

public class Program

{

    public static void Main()

    {

    var m_MinTemperature = 30M;

    var m_MaxTemperature = 66.9M;

​

    Console.WriteLine("#1:" + Math.Round(9.15M, 1, MidpointRounding.AwayFromZero));

    Console.WriteLine("#2:" + (9.15M).ToString("G17"));

    var r = ToCelcius(m_MinTemperature) + ToCelcius(m_MaxTemperature);

    Console.WriteLine("#3:" + r.ToString("G17")); 

    Console.WriteLine("#4:" + (r / 2M).ToString("G17"));

    Console.WriteLine("#5:" + Math.Round((r / 2M), 1, MidpointRounding.AwayFromZero).ToString("G17"));

    }

​

​

    static decimal ToCelcius(decimal fahrenheit)

    {

        return Math.Round((fahrenheit - 32M) / 1.8M, 1, MidpointRounding.AwayFromZero);

    }   

}