ehdonhon is right -- you're always better off here if you include something you've tried, especially if you tell us what you got from it, so we can see how it differed from what you say you want (this sometimes helps us get a better idea of what you really want).

In fact, I'm only guessing now that you might want something like this:

@another_array = map { $_ * $number_from_stdin } @large_array;
[download]

or maybe you'd be more comfortable with something less compact:

foreach my $val ( @large_array ) {
   push @another_array, $val * $number_from_stdin;
}
[download]

which does the same thing, but may be less mystifying to a larger audience of programmers who may be unfamiliar with Perl.

So, have you been reading any relevant books or documentation? You might find that helpful as well...