You question is a little unclear: Do you have one scaling factor, or one per element of the array. I think you are wanting 1 scale facter for the entire array. So you might try:
my @source = (1..10);
my $scale = <>; # get user input
my @result = map { $_ * $scale } @source;
print "original: @source\n";
print "scaled by $scale: @result\n";