AXQH
      ----------
 HQHH ) AXUWFTXF
       -THCHX
        =====
         XQWAT
        -CHTHA
         =====
          QQAHX
         -XHWHT
          =====
           HTFUF
          -QHFHW
           =====
            THUH

base: 10
symbols: ACFHQTUWXY
difficulty: intermediate
missing: Y