PPQQ
      +---------
NMJRJ | FJMMAAUN
       -UNAUP
        =====
         FFUNA
        -UNAUP
         =====
         JQJANU
        -JMAJMQ
         ======
          JQPFJN
         -JMAJMQ
          ======
           JFQQQ

base: 10
letters: AFJMNPQRUX
missing: X
difficulty: medium
restrictions: two multiplications