sub ratio_change {...}
my @args = ($start_value, $start_total, $new_value, $new_total);
ratio_change @args;   # Same result as:
ratio_change $start_value, $start_total, $new_value, $new_total;

##</code><code>##

sub ratio_change ($$$$) {...}
my @args = ($start_value, $start_total, $new_value, $new_total);
ratio_change @args;   # Eeks. Won't do what you think it does.
ratio_change $start_value, $start_total, $new_value, $new_total;

##</code><code>##

sub foo ();
sub foo ($);
sub foo (&@);
sub foo (\@@);
sub foo (\%@);