(define series_sum
 ( lambda (n)
  (if (= n 0) 0 
    (+ (/ 1 (* n (+ n 1))) (series_sum(- n 1)))
  ) ) )
(display (series_sum 10))
(display " ")
(display (series_sum 100))
(display " ")
(display (series_sum 1000))
(display " ")
(display (series_sum 10000))

10/11 100/101 1000/1001 10000/10001