If I understand yout Problem right this might do:

my $ptr;
for ( my $i = 0; $i < @numbers; $i++ ){

 $ptr->{$i}->{ number } = $numbers[$i];
 $ptr->{$i}->{ sign }   = $signs[$i];

}
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This is a reference for a hash. You can now get your values back as:

while (@new_numbers){
 my $i = $_;
 if ( defined $ptr->{$i} ){
  print $ptr->{$i}->{ sign }.$ptr->{$i}->{ number }."\t".$i;
 }
}
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This is not tested but should work. It uses references to a hash. Alternatively you might want to make $i part of the keys:

$hash{ $numbers[$i].":".$i } = $signs[$i];
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But it would be much more complicated sorting the keys out. Hope this is what you wanted.