There is a two-dimensional array. The sum of the second row and the product of the first column are calculated. The initial matrix and calculation results are displayed.

Working with correct rows and columns

    internal class Program
    {
        static void Main(string[] args)
        {
            int[,] arrayNumbers =
            {
                {1, 2, 3},
                {4, 5, 6},
            };
            int sum = 0;
            int multiply = 1;
            int column1 = 0;
            int line2 = 1;

            for (int i = 0; i < arrayNumbers.GetLength(0); i++)
            {
                for (int j = 0; j < arrayNumbers.GetLength(1); j++)
                {
                    Console.Write(arrayNumbers[i, j] + " ");
                }

                Console.WriteLine();
            }

            for (int i = 0; i < arrayNumbers.GetLength(0); i++)
            {
                multiply *= arrayNumbers[i, column1];
            }

            for (int i = 0; i < arrayNumbers.GetLength(1); i++)
            {
                sum += arrayNumbers[line2, i];
            }

            Console.WriteLine($"fist column multiply = {multiply} and second line sum = {sum}");
        }
    }