651
      +--------
98C85 | 3657606
       -8EF7C
        =====
         432D0
        -4414F
         =====
          C03D6
         -CA6AB
          =====
           6D00

base: 16
letters: 0123456789ABCDEF
difficulty: hard
hints: 9 greater than 0, 8 << 0, D << 6