using System;

public class Program

{

    public static void Main()

    {

        double coord = 123;

        double? offset1000 = 1000;

        double? offsetnull = null;

        double result1 = coord + offset1000 ?? 0;

        double result2 = coord + (offsetnull ?? 0);

        double result3 = coord + offsetnull ?? 0;       

        Console.WriteLine($"Result1: {result1}");

        Console.WriteLine($"Result1: {result2}");

        Console.WriteLine($"Result1: {result3}");

    }

}