4275
      +---------
86C36 | A890BA0B
       -15C4B
        =====
        81960A
       -849B55
        ======
         808420
        - 67528
         ======
          839CCB
         -874B07
          ======
           841C1

base: 13
letters: 0123456789ABC
difficulty: intermediate
restrictions: no multiplication