Difference between throw and throw ex in c# with simple example

Using throw statement-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace throw_throwex
{
    class Program
    {
        static void Main(string[] args)
        {
            //difference between throw and throw ex in c#
            try
            {
                int x = calc(5, 0);
                Console.WriteLine(x);
                Console.ReadLine();
            }
            catch (Exception)
            {
                throw;
            }
        }
        public static int calc(int a, int b)
        {
            return a / b;
        }
    }
}

Output:

Using throw ex statement-

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace throw_throwex
{
    class Program
    {
        static void Main(string[] args)
        {
            //difference between throw and throw ex in c#
            try
            {
                int x = calc(5, 0);
                Console.WriteLine(x);
                Console.ReadLine();
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }
        public static int calc(int a, int b)
        {
            return a / b;
        }
    }
}