QJJQ
      +---------
JFCYQ | CQYLQXYQ
       -CLFYC
        =====
         JETTX
        -JFCYQ
         =====
          LLFFY
         -JFCYQ
          =====
           CXJXQ
          -CLFYC
           =====
            CCFT

base: 10
letters: CEFJLNQTXY
difficulty: hard
restrictions: one multiplication
missing: N