GPQP
      +---------
JERGW | PMNJPQQM
       -MNPMW
        =====
        JLEEPQ
       -JJJEQW
        ======
         JNRRQQ
        -JLPELW
         ======
          JLGMQM
         -JJJEQW
          ======
           JNJWM

base: 10
letters: EGJLMNPQRW
difficulty: hard
restrictions: no multiplication