#!/usr/bin/perl
use strict;
use warnings;

my %HASH;
open(F1,"file1");
while (<F1>) {
	chomp;
	my ($k,$v) = split /\s+/,$_,2;
	$HASH{$k} = $v;
}
close(F1);

open(F2,"file2");
while (<F2>) {
	chomp;
	my ($k,$v) = split /\s+/,$_,2;
	if (exists $HASH{$k} ) {
		$HASH{$k} *= $v;
	}else{
		$HASH{$k} = $v;
	}	
}
close(F2);

# write output to file
open(OUT,">newfile");
while (my ($k,$v) = each %HASH) {
	print OUT "$k $v\n";
}
close(OUT);