Square Root Problem 18

C# Hi! i don't know where is my mistake. with this cod i have the results more precise than in the exercises, but the test says to me i am wrong. Can someone help me to describe my mistake?

My cod:

   class Program
     {
      static void Main(string[] args)
      {
        StringBuilder answer = new StringBuilder();
        int n = int.Parse(Console.ReadLine());
        for (int i = 0; i < n; i++)
        {
            string[] line = Console.ReadLine().Split(' ');
            int[] arr = line.Select(x => int.Parse(x)).ToArray();
            int numberSteps = arr[1];
            int number = arr[0];
            double  r = 1;
            for (int j = 0; j < numberSteps; j++)
            {
                 r = (r + number / r) / 2;
                 r = Math.Round(r, 12);
            }
            answer.Append(r);
            answer.Append(" ");
        }
        Console.WriteLine(answer);
        Console.WriteLine();
       }
    }

My answers: 8,732993701398 152,361855184417 33,5 28,12472222085 8,246211251236 7592,49982708812 4097,5 38,392831314275 4,126106627581 155,735313093754 134,884803684064 209,442801425437

Test answers: 8.7329937014 152.361855184 33.5 28.1247222209 8.24621125124 7592.49982709 4097.5 38.3928313143 4.12610662758 155.735313094 134.884803684 209.442801425

Data: 12 70 4 23214 10 66 1 791 13 68 7 60719 3 8194 1 1474 8 17 4 24121 9 3981 5 34139 8

*Results should have precision of 1e-7 = 0.0000001 or better!

Thank you!

thank you friend! :)

*I added the line:

 System.Threading.Thread.CurrentThread.CurrentCulture = new System.Globalization.CultureInfo("en-US");

and everything OK!