How to pass parameters using param array in C# method?

public int AddElements(params int[] arr) {
}

using System;

namespace Program {
   class ParamArray {
      public int AddElements(params int[] arr) {
         int sum = 0;

         foreach (int i in arr) {
            sum += i;
         }
         return sum;
      }
   }

   class Demo {
      static void Main(string[] args) {
         ParamArray app = new ParamArray();
         int sum = app.AddElements(300, 250, 350, 600, 120);

         Console.WriteLine("The sum is: {0}", sum);
         Console.ReadKey();
      }
   }
}

The sum is: 1620