Input string was not in the correct format

static void Main(string[] args)
       {
           int numberOne;
           int numberTwo;
           int numberThree;
           int numberFour;
           int numberFive;

           Console.WriteLine("Enter the first integer");
           numberOne = int.Parse(Console.ReadLine());

           Console.WriteLine("Enter the second integer");
           numberTwo = int.Parse(Console.ReadLine());

           Console.WriteLine("Enter the third integer");
           numberThree = int.Parse(Console.ReadLine());

           Console.WriteLine("Enter the fourth integer");
           numberFour = int.Parse(Console.ReadLine());

           Console.WriteLine("Enter the fifth integer");
           numberFive = int.Parse(Console.ReadLine());


           Arithmetic arithmetic = new Arithmetic();
           arithmetic.ArithmeticMethod();
       }
   }

public void ArithmeticMethod()
      {
          int numberOne;
          int numberTwo;
          int numberThree;
          int numberFour;
          int numberFive;

          numberOne = int.Parse(Console.ReadLine());

          numberTwo = int.Parse(Console.ReadLine());

          numberThree = int.Parse(Console.ReadLine());

          numberFour = int.Parse(Console.ReadLine());

          numberFive = int.Parse(Console.ReadLine());

          Sum(numberOne, numberTwo, numberThree, numberFour, numberFive);
          Average(numberOne, numberTwo, numberThree, numberFour, numberFive);
          Product(numberOne, numberTwo, numberThree, numberFour, numberFive);
          SmallestNumber(numberOne, numberTwo, numberThree, numberFour, numberFive);
          LargestNumber(numberOne, numberTwo, numberThree, numberFour, numberFive);
      }
      public static int Sum(int numberOne, int numberTwo, int numberThree, int numberFour, int numberFive)
      {
          int sum;
          sum = numberOne + numberTwo + numberThree + numberFour + numberFive;
          Console.WriteLine($"the sum of the integers is {sum}");
          return sum;
      }