        represents 'number' in base 16 ``scientific notation,''
            e.g.:

               672.0 = '2A^3' = ( 2/16 + 10/( 16**2 ) ) * 16**3

            and

               -11.0 = '-B^1' = - ( 11/16 ) * 16**1.

            The following table describes the character set used to
            represent the hexadecimal digits and their corresponding
            values.

                 Character    Value         Character    Value
                 ---------    ------        ---------    ------
        