AA4A
      +---------
94782 | 27174785
       -252A6
        =====
         2A887
        -252A6
         =====
           79985
          -252A6
           =====
           5A303

base: 11
letters: 0123456789A
difficulty: hard
hints: 0 << 9, 2 << 1, 5 << 1