XXJX
      +---------
PJJFX | FPPJEFNJ
       -PJJFX
        =====
         JENJF
        -PJJFX
         =====
         WQGNPN
        -NURENJ
         ======
           JFXGJ
          -PJJFX
           =====
           NEFXG

base: 11
letters: EFGJNPQRUWX
difficulty: medium
restrictions: no multiplication