use warnings;
use strict;

sub round5 {
    my ($number) = @_;

    my $remainder = $number % 5;

    if ($remainder < 3) {
        return $number - $remainder; 
    } else {
        return $number - $remainder + 5;
    }
}

for (0..10) {
    print "$_ rounded is " . round5($_) . "\n";
}