use strict;
use warnings;

my $entered_value;

my $min_allowed = 1;
my $max_allowed = 5;

if($entered_value =~ /^\d+\z/s and
   ($entered_value >= $min_allowed and $entered_value <= $max_allowed))
   {
    do_magical_processing($entered_value);
    }
else{
    print "value must be a number no less than $min_value and not greater than $max_value\n";
}