88B2
      +---------
B58A3 | 4742C556
       -2794A
        =====
        715485
       - 2794A
        ======
         8A5375
        -8764B8
         ======
          9036B6
         -967735
          ======
           78C88

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