????????
      +---------
FA9A8 | 02277925
       -95D59
        =====
        C02619
       -C9BCD9
        ======
          B51D2
         -8E99F
          =====
          A43935
         -A00C79
          ======
          ??????

base: 16
letters: 0123456789ABCDEF
difficulty: hard