Try following logic :



/ Loop through all operands in the multiplication table.
        for (int a = 1; a < firstNumber; a++)
        {
            for (int b = 1; b < secondNumber; b++)
            {
                // Write the multiplied number.
                Console.Write((a * b).ToString("00 "));
            }
            // New line.
            Console.WriteLine();
        }