use strict;
use warnings;

sub magnitude {
   my ($n, $p) = @_;
   $p ||= 16;   # Num of significant digits. 16 max for doubles
   return 0 + ( sprintf('%.*e', $p-1, $n) =~ /e(.*)/ )[0];
}

sub movement {
   my ($old, $new) = @_;
   my $m = magnitude($old);
   return 0 + sprintf '%.0f', ($new-$old) * 10**(4-$m);
}

printf("%+.0f\n", movement(@ARGV));

##</code><code>##

>perl movement.pl 1.0025 1.003
+5

>perl movement.pl 10.025 10.03
+5

##</code><code>##

>perl movement.pl 98000 99000
+1000

>perl movement.pl 99000 100000
+1000

>perl movement.pl 100000 99000
-100

>perl movement.pl 99000 98000
-1000