use warnings; use strict; use Tk; use Devel::Peek; my $scale = '22.5 '; # note the space in the output as well my $foo = 0 + $scale; # use in numeric context (set NV and IV) Dump($scale); my $mw = MainWindow->new; $mw->Entry(-textvariable=>\$scale)->pack; $mw->bind("",\&calc); calc(); MainLoop; sub calc { print "str: <$scale> / num: <".(0+$scale)."> \n"; }