MathFunctionsHW-YuvalA(FromUser)

using System;

namespace ConsoleApplication25
{
    class App
    {
        static void Main()
        {
            MathExerciseNine();
            MathExerciseTwelve();
            MathExerciseThirteen();
            MathExerciseFiftheen();
        }
        static void MathExerciseNine()
        {
            double n1, n2, n3, avg;
            Random rnd = new Random();
            n1 = (double) rnd.Next(101, 1000) / 1000;
            n2 = (double)rnd.Next(101, 1000) / 1000;
            n3 = (double)rnd.Next(101, 1000) / 1000;
            avg = (n1 + n2 + n3) / 3;
            Console.WriteLine(avg);
        }
        static void MathExerciseTwelve()
        {
            float a, b, c, size, p;
            a = float.Parse(Console.ReadLine());
            b = float.Parse(Console.ReadLine());
            c = float.Parse(Console.ReadLine());
            p = (a + b + c) / 2;
            size = (float) Math.Sqrt(p*(p-a)*(p-b)*(p-c));
            Console.WriteLine("Triangle size: {0}", size);
        }
        static void MathExerciseThirteen()
        {
            decimal num = decimal.Parse(Console.ReadLine());
            int agorot = (int)(num * 100) % 100;
            Console.WriteLine("{0} shekels and {1} agorot.", (int)num, agorot);
        }
        static void MathExerciseFiftheen()
        {
            double num = double.Parse(Console.ReadLine());
            double keptForLater = ((num * 10) % 10) / 10;
            if (keptForLater >= 0.5)
                keptForLater += -1;
            num = Math.Round(num);
            Console.WriteLine("Rounded mark: {0}, kept for final mark: {1}", num, keptForLater);
        }
    }
}