DB<253> @a{a..c}=1..3
 => (1, 2, 3)

  DB<254> @b{b..d}=6..8
 => (6, 7, 8)

  DB<255> $c{$_}=$a{$_}+$b{$_} for (keys %a,keys %b)
 => ""

  DB<256> \%c
 => { a => 1, b => 8, c => 10, d => 8 }