CMUCX
     +---------
PMCQ | XYQTUYJC
      -PMCQ
       ====
       UTMXU
      -UUMYM
       =====
         JQQY
        -JHTP
         ====
          QPPJ
         -PMCQ
          ====
          UJTUC
         -UQCHU
          =====
           UUCJ

base: 10
letters: CHJMPQTUXY
difficulty: medium
restrictions: no multiplication