(define (range a b)
  (if (> a b) '() (cons a (range (add1 a) b))))

(define (sum lst)
  (foldl + 0 lst))

(define (sqr a)
  (* a a))

(define (problem6 v)
  (let ((r (range 1 v)))
  (- (sqr (sum r)) (sum (map sqr r)))))

(print (problem6 10))
(print (problem6 100))