FAEQ
      ----------
 QEQQ ) FACYWXAW
       -XQNQA
        =====
         AEYFX
        -NQXQF
         =====
          EEFQA
         -AQYQX
          =====
           QXWCW
          -EQWQY
           =====
            XQCQ

base: 10
symbols: ACEFNQUWXY
difficulty: intermediate
missing: U