????????
      +---------
AA260 | B3B2EED4
       -3BAA9
        =====
        1DC6DE
       -1CD097
        ======
         42DAAD
        -4033D3
         ======
          786614
         -4D4955
          ======
          ??????

base: 15
letters: 0123456789ABCDE
difficulty: medium
attributes: good referencing