4294
      +---------
86CBA | 05A900B5
       -58CD9
        =====
        44E860
       -46DA97
        ======
         695B8B
        -653E04
         ======
           9A295
          -58CD9
           =====
           69A4C

base: 15
letters: 0123456789ABCDE
difficulty: hard
missing: 1