????????
      +---------
0155E | 9AF9EF0B
       -984A0
        =====
         71D3F
        -5F984
         =====
          CA8A0
         -A3B25
          =====
           BA16B
          -B27A7
           =====
           ?????

base: 16
letters: 0123456789ABCDEF
difficulty: medium