RRTR
      +---------
CRFNT | HXRFHUTM
       -FCXTJ
        =====
        URJUCU
       - FCXTJ
        ======
         NQNMMT
        -EHUTJT
         ======
          URFUQM
         - FCXTJ
          ======
           NNNEU

base: 12
letters: CEFHJMNQRTUX
difficulty: medium
restrictions: no multiplication