C342
      +---------
03604 | 205B446C
       -9AB95
        =====
        CB8434
       -C5A25B
        ======
         C99706
        -C74378
         ======
          05222C
         -B86A81
          ======
           0B2AB

base: 13
letters: 0123456789ABC
difficulty: medium
restrictions: no multiplication