D231
      +---------
FDF5B | D6653949
       -D4DCE
        =====
         B59A9
        -2654C
         =====
          8F664
         -E50FD
          =====
           661D9
          -6D8DB
           =====
            5E0D

base: 16
letters: 0123456789ABCDEF
difficulty: hard
missing: 7