Here we take a simple example of LINQ. We just compare a number with a number of digits:
int[] digits = { 5, 4, 1, 7, 9, 8, 6, 7, 4, 5 };
var num =
from n in digits
where n >= 6
select n;
Console.WriteLine("Numbers < 5:");
foreach (var x in num)
{
Response.Write(x);
}