Recognized operators fall into one of two categories:

arithmetical operators
   +   addition
   -   subtraction
       unary minus
   *   multiplication
   /   division

   NOTE: * and / have priority over + and -


logical operators
   # OR
   & AND

   NOTE: & has priority over #.
         Priority in combinations of arithmatical and logical operations
         is not defined - use brackets to enforce your needs.