PFQN
      +---------
TPRPX | NPFXNTEE
       -TPRPX
        =====
        XLTGTT
       -GTNGLF
        ======
         XYLXFE
        -XPLYJJ
         ======
          XNQYTE
         -XYPQRY
          ======
           GEFRP

base: 12
letters: EFGJLNPQRTXY
difficulty: intermediate
restrictions: no multiplication