Printing parts of an array

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C#

I'm trying to run a 2 methods to gather statistics on different sorting methods, I have Shell sort and Gnome sort. My problem is that I have to have the console print out the first and last 20 numbers from the original array. My problem is that the program sorts the original array and because of this when I call the methods again they are wrong because the array has been sorted, any help would be appreciated, here's what I tried so far:
Here's is where the program sorts it:

int[] Number = new int[1000];  //// create a and fill a random array
          Random numb = new Random();

          for (int i = 0; i < Number.Length; i++)
          {
              Number[i] = numb.Next(100, 999);
              Console.WriteLine(Number[i]);  //// display the instances
          }
          GnomeSort(Number);
          ShellSort(Number);
          statement = 0;
          statements = 0;

          Console.WriteLine("Press any key to display the first twenty numbers");
          Console.ReadLine();
          for (int j = 0; j < 20; j++)
          {
              Console.WriteLine(Number[j]);
          }
          GnomeSort(Number);
          ShellSort(Number);

I also tried using two loops:

for (int i = 0; i < 1000; i += 20)
{

    for (int j = i; j < i + 20; j++)
    {
        array1[j] = Number[i];
        Console.WriteLine("" + array1[j]);

    }
}

And I also made the two different displays into methods; any pointing in the right direction would be appreciated, I have tried other approaches too like a foreach loop, I just need to know why this is happening and what would be the best approach to fix it. Thank You.