CXX
       +---------
FXRCXU | QCRQRUNH
        -FXRCXU
         ======
         CRULFUN
        -CLCNXHU
         =======
          CHACCNH
         -CLCNXHU
          =======
           XULQFH

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