using System;

using System.Linq;

public class Program

{

    public static void Main()

    {

        // sum the numbers from 0 to 9 that are divisable by 3 and 5

        var intValue = 10;

        int[] arr = Enumerable.Range(0, intValue).ToArray();

        var sum = arr.Sum(s => {

            if (s % 3 == 0 || s % 5 == 0)

                return s;   

            else 

                return 0;

        });

        Console.WriteLine(sum);

    }

}

​