9940
      +---------
DB035 | 60A69836
       -DB035
        =====
         EC038
        -DB035
         =====
         85CC93
        -8C8629
         ======
          74FDB6
         -7A305D
          ======
           7E3E9

base: 16
letters: 0123456789ABCDEF
difficulty: hard
missing: 1