Just an addition to what the others already mentioned above: If you want to force numeric key sorting, you should use a custom sort block, like this:

#!perl

use strict;
use warnings;

my $href = { '6' => '154', '4' => '152', '1' => '80', '3' => '151', '8
+' => '150' };

my $key   = (sort {$a <=> $b} keys %$href)[0];
my $value = $href->{$key};

print "$key => $value\n";

__END__
1 => 80
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