XENM
      +---------
FMTMF | YFTTGNTM
       -XUNMX
        =====
         PUTCN
        -ENUME
         =====
          NNFTT
         -NGXMN
          =====
            ETUM

base: 11
letters: CEFGMNPTUXY
difficulty: intermediate
restrictions: no multiplication