1A58
      +---------
75924 | 49AC598B
       -A1557
        =====
         27919
        -3179B
         =====
          C8708
         -423BC
          =====
           9BA5B
          -80A39
           =====
            B0C7

base: 13
letters: 0123456789ABC
difficulty: medium
missing: 6