...
my $in_data_section = 0;
while (<FILE>){
    chomp;
    if ($in_data_section) {
        my @numbers = split;
        #...
    }
    $in_data_section = 1 if m/^Number/;
}

##</code><code>##

while (<FILE>){
    chomp;
    if (/^Number/) {
        # found header, now we're expecting two lines with numbers
        for (1..2) {
            $_ = <FILE>;
            chomp;
            my @numbers = split;
            #...
        }
    }
    #... do other stuff
}