(define (range min max)
  (if (> min max) null
      (cons min (range (+ 1 min) max))))

; better
(define (x+y^2 x y)
    (let ((sum (+ x y))) (* sum sum)))

(define (math!! x y)
  (let* ((sum (+ x y))   ; sum = x+y
        (sum2 (+ sum 2)))   ; sum2 = (x+y+2)
        (* (* sum sum) (* sum2 sum2))))        ; (x+y)^2 * (x+y+2)^2