or download this
my $limit_3 = param("limit_3");
my $limit = param("limit");
...
print qq($limit);
<form method="POST" action="add_to_the_number.pl"><input type="hidden"
+ name="limit_3" value="10"><input type="hidden" name="limit" value="$
+limit"><input type="submit" name="action" value="Next"></form>