>perl -wMstrict -le
"my $ubar   =  60_0;
 my $q_ubar = '60_0';
 print $ubar;
 print $q_ubar;
 print 'unequal' if $ubar != $q_ubar;
 print 'equal'   if  60   == $q_ubar;
"
600
60_0
Argument "60_0" isn't numeric in numeric ne (!=) at -e line 1.
unequal
equal