D897
    +-------
C74 | 3B330B
     -315
      ===
       793
      -85D
       ===
        2C0
       -50E
        ===
         EDB
        -EC6
         ===
          ED

base: 15
letters: 0123456789ABCDE
difficulty: hard
hints: 3 << 2, E << 6 << B
missing: A