NTJW
      +---------
LMLJM | QLXWLEEQ
       -LMLJM
        =====
        MUNWUE
       -MNHFRW
        ======
          RLFFEQ
         -RMLRUE
          ======
           UEXUX

base: 13
letters: EFHJLMNQRTUWX
difficulty: hard
restrictions: one multiplication