Untitled

using System;
using System.Threading;

class Program
{
    static void Main(string[] args)
    {
        Thread t = new Thread(() =>
        {
            int sum = 0;
            for (int i = 1; i <= 100; i++)
            {
                sum += i;
            }
            Console.WriteLine("Sum: " + sum);
        });
        t.Start();
        t.Join();
        Console.ReadKey();
    }
}