using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        var numbers = new[] { 2, 4, 6, 8, 10};

​

        var result = numbers.Aggregate((x, y) => x + y);

        // (2 + 4) = 6, (6 + 6) = 12, (12 + 8) = 20, (20 + 10) = 30

        Console.WriteLine(result);

    }

}