DEMO
> perl -de0
  DB<2> use IO::Handle;              # just an arbitrary class from core

  DB<3> $io = IO::Handle->new();

  DB<4> p "$io"                      # <-- Stringification
IO::Handle=GLOB(0x32c5c70)
  DB<5> p 0+$io                      # <-- Numification
53238896       
  DB<6> p $io + $io                  # nummeric operation
106477792
  DB<7> p $io . $io                  # string operation
IO::Handle=GLOB(0x32c5c70)IO::Handle=GLOB(0x32c5c70)
  DB<8>

##</code><code>##

a='1'; 1+a
'11'