3B07
      +---------
37C67 | 408C7C2C
       -0C42C
        =====
        330D5C
       -3E591C
        ======
          AD392
         -8EC89
          =====
          E2832C
         -E22CA5
          ======
            182B

base: 15
letters: 0123456789ABCDE
difficulty: hard
missing: B