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

open (NUMBERS, '<', "numbers.txt") or die "Unable to open numbers.txt for reading : $!";
open (NAMES, '<', "names.txt") or die "Unable to open names.txt for reading : $!";

my @namevals = map {chomp; [split /\t/ , $_ , 2]} <NAMES>;

while (<NUMBERS>)
{
  s/\s//gs;
  my $current = $_ + 0;
  map {print $_->[0]," matched $current\n"
       if (abs($_[1] - $current) <= 0.5);}
    @namevals;
}