FMM
      +---------
YTTMH | FRUJRMNM
       - YTTMH
        ======
         UFTHUN
        -TCNURN
         ======
          UFJURM
         -TCNURN
          ======
           UCRRY

base: 11
letters: CFHJMNPRTUY
missing: P
difficulty: medium
restrictions: no multiplication