CCEM
      +---------
PCEJJ | PGQWMMWN
       -PCEJJ
        =====
         JGQJM
        -PCEJJ
         =====
         CJWYJW
        -CPENNG
         ======
          CLQWYN
         -CQMJEM
          ======
           XNCWW

base: 12
letters: CEGJLMNPQWXY
difficulty: intermediate
restrictions: no multiplication