LLHR
      +---------
NPMNH | TEEURLXT
       -NPMNH
        =====
        LEHTYL
       - NPMNH
        ======
         RPUFEX
        -RRXPUM
         ======
          XFFTLT
         -MTNUYP
          ======
           GXEMH

base: 13
letters: EFGHLMNPRTUXY
difficulty: medium
restrictions: no multiplication