????????
      +---------
51532 | 7497B85B
       -75B11
        =====
         32038
        -51532
         =====
         142445
        -1B3877
         ======
          20417B
         -25B055
          ======
          ??????

base: 12
letters: 0123456789AB
missing: A 6
difficulty: intermediate
hints: 6 << 5