65A0
      +---------
919B6 | 245B06A3
       -919B6
        =====
        B5D7B6
       -6EAC85
        ======
         3668DA
        -5E543A
         ======
          64D973
         -695110
          ======
           5872B

base: 15
letters: 0123456789ABCDE
difficulty: medium