(reduce-left - '(1 2 3 4 5))

-13

(reduce-right - '(1 2 3 4 5))

3

(reduce-left string-append (list "The" " " "End"))

"The End"

(reduce-left append 
  (list (list 1 2 3) (list 'a 'b 'c)))

(1 2 3 a b c)