Кімде информатика тжб бар​

Using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Введи A");
            double A = double.Parse(Console.ReadLine());
            Console.WriteLine("Введи B");
            double B = double.Parse(Console.ReadLine());
            Console.WriteLine("1 - сложение, 2 - вычитание");
            int n = int.Parse(Console.ReadLine());
            switch (n)
            {
                case 1:
                    {
                        double Y = A + B;
                        Console.WriteLine(Y);
                        break;
                    }
                case 2:
                    {
                        double Z = A - B;
                        Console.WriteLine(Z);
                        break;
                    }
                default:
                    {
                        Console.WriteLine("Выбрана несуществующая операция");
                        break;
                    }
            }
            Console.ReadKey();
        }
    }
}

Приоритеты операций: 
! инверсия значения
& побитовое И
^ исключающее ИЛИ
| побитовое ИЛИ

7(10) = 00111(2)
11(10) = 01011(2)
21(10) = 10101(2)
25(10) = 11001(2)
31(10) = 11111(2)

11 & 7 = 01011 & 00111 = 00011
11 & !7 = 01011 & 11000 = 01000
11 & 7 | 11 & !7 = 00011 | 01000 = 01011

11 & 7 = 01011 & 00111 = 00011
!11 & 7 = 10100 & 00111 = 00100
11 & 7 | !11 & 7 = 00011 | 00100 = 00111

7 & 31 = 00111 & 11111 = 00111
(7 & 31 | (11 & 7 | !11 & 7)) = 00111 | 00111 = 00111

25 & 31 = 11001 & 11111 = 11001
25 | 25 & 31 = 11001 | 11001 = 11001

(7 & 31 | (11 & 7 | !11 & 7)) & (25 | 25 & 31) = 00111 & 11001 = 00001

31^(11 & 7 | 11 & !7) = 11111 ^ 01011 = 10100
31^(11 & 7 | 11 & !7) ^ 21 = 10100 ^ 10101 = 00001

(7 & 31 | (11 & 7 | !11 & 7)) & (25 | 25 & 31) ^ 21 = 00001 ^ 10101 = 10100

31^(11 & 7 | 11 & !7) ^ 21 | (7 & 31 | (11 & 7 | !11 & 7)) & (25 | 25 & 31) ^ 21 =
00001 | 10100 = 10101

10101(2) = 21(10)