Use of uninitialized value

[B. Fongo]

What may be wrong with my codes?  Perl complains of use of uninitialized
value at addition and in range (or flop).

Thanks

#########################################

#!/usr/bin/perl -w
use strict;

my ($xi, $i, @numbers, @slice);
@numbers = (1..10);
$i = 0;
$xi = 0;

open(RS, ">perd.dat") || die "Could not open file. $!\n";
for (my $z = 0; $z <= $#numbers; $z++){
                
                
                foreach  (@numbers){
                        @slice = @numbers[$xi,  $numbers[$i] ..
$numbers[$i]+4]; # Use of uninitialized value at here?
                        print RS "@slice\n";
                    $i++;
                }
                
                $xi++;
                
}
                
  close(RS);

###################################
Babs