FXUF
      +---------
AMEXM | UHHHFGFA
       -FTAGR
        =====
        AFGARG
       -AFFMMT
        ======
          EGMAF
         -EUMTF
          =====
           MXUHA
          -FTAGR
           =====
           AFFAE

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