GGLCC
     +---------
RCQP | ECPGNLGE
      -RCQP
       ====
        QGGN
       -RCQP
        ====
        GRLNL
       -GXREP
        =====
         LXRLG
        -LLGRP
         =====
          LNNGE
         -LLGRP
          =====
           CCXE

base: 10
letters: CEFGLNPQRX
difficulty: medium
restrictions: no multiplication
missing: F