C#

class Box
   {
   ...
   }

using System.Windows.Forms;

namespace MyNamespace
{
    public class Box : Control
    {

    }
}

using System.Linq;

namespace SomeNamespace
{
    public static class SomeExtensionClass
    {
        /// <summary>
        /// computes the actual decimal value from an IBM "Packed Decimal" 9(x)v9 (COBOL) format
        /// </summary>
        /// <param name="value">byte[]</param>
        /// <param name="precision">byte; decimal places, default 2</param>
        /// <returns>decimal</returns>
        public static decimal FromPackedDecimal(this byte[] value, byte precision = 2)
        {
            if (value.Length < 1)
            {
                throw new System.InvalidOperationException("Cannot unpack empty bytes.");
            }
            double power = System.Math.Pow(10, precision);
            if (power > long.MaxValue)
            {
                throw new System.InvalidOperationException(
                    $"Precision too large for valid calculation: {precision}");
            }
            string hex = System.BitConverter.ToString(value).Replace("-", "");
            var bytes = Enumerable.Range(0, hex.Length)
                     .Select(x => System.Convert.ToByte($"0{hex.Substring(x, 1)}", 16))
                     .ToList();
            long place = 1;
            decimal ret = 0;
            for (int i = bytes.Count - 2; i > -1; i--)
            {
                ret += (bytes[i] * place);
                place *= 10;
            }
            ret /= (long)power;
            return (bytes.Last() & (1 << 7)) != 0 ? ret * -1 : ret;
        }
        /// <summary>
        /// computes the actual decimal value from an IBM "Packed Decimal" 9(x)v9 (COBOL) format
        /// </summary>
        /// <param name="value">string; EBCDIC</param>
        /// <param name="precision">byte; decimal places, default 2</param>
        /// <returns>decimal</returns>
        public static decimal FromPackedDecimal(this string value, byte precision = 2)
        {
            return System.Text.Encoding.GetEncoding("IBM037")
                       .GetBytes(value).FromPackedDecimal(precision);
        }
    }
}