71C9
      +---------
1147C | 1A09A779
       -1147C
        =====
         E3D97
        -44588
         =====
         768C97
        -74E606
         ======
          791939
         -7B05EB
          ======
            8EE7

base: 15
letters: 0123456789ABCDE
difficulty: hard
missing: 2