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

my %sum_of;

# read linewise from filehandle
while ( my $line = <DATA> ) {

  # remove linebreak; for details, see: perldoc -f chomp
  chomp $line;

  # split at whitespace characters; see: perldoc -f split
  # change \s to \t if only tabs are allowed; 
  # remove + from pattern, if only one whitespace separates the columns
  my ( $name, @fields ) = split m{\s+}, $line;
  
  # support multiple columns; sum up the fields per column
  for my $idx ( 0 .. $#fields ) {
    
    # create a Hash of Arrays and store the sums; see: perldoc perldsc
    $sum_of{ $name }->[$idx] += $fields[$idx];
  }
}

# print result
for my $name ( keys %sum_of ) {
  print join "\t", $name, @{ $sum_of{$name} };
}

#

__DATA__
AA 12
bb 34
AA 76
cc 98
dd 76
bb 98