foreach (qw( -845 4/3 1.25 )) {
   /^[-+]?\d{3}$/ && do {
      print("$_ is a three digit integer, with a possible sign.\n");
     #next;
   };

   /^-/ && do {
      print("$_ starts with a minus sign\n");
     #next;
   };

   /\// && do {
      print("$_ has a / in it.\n");
     #next;
   };
}

__END__
output
======
-845 is a three digit integer, with a possible sign.
-845 starts with a minus sign
4/3 has a / in it.