-2 => '+0.000000',

##</code><code>##

              -1 => '+0.000000',

##</code><code>##

            -100 => '+1.0e-999',
             -10 => '+1.00e-99',
              -5 => '+1.000e-9',

##</code><code>##

              +9 => '+1.000e+9',
             +99 => '+1.000e99',
          +99999 => '+1.00e999',