using System;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

        int[] numbersA = { 0, 2, 4, 5, 6, 8, 9 };

        int[] numbersB = { 1, 3, 5, 7, 8 };

        var pairs = numbersA.SelectMany(a => numbersB.Where(b => b>a)

                    .Select(b => new { a, b }));

        foreach(var pair in pairs)

            Console.WriteLine(String.Format("a={0},b={1}",pair.a,pair.b));

    }

}