diff --git a/day07.scm b/day07.scm
index a35bf16..76f3e98 100644
--- a/day07.scm
+++ b/day07.scm
@@ -7,31 +7,25 @@
 (define numbers (map string->number (string-split (read-line) ",")))
 
 ; PART 1
-(define sorted (sort numbers <))
-(define median (list-ref sorted (floor/ (length numbers) 2)))
-
-(define (part1)
-  (foldl
-   (lambda (x y) (+ x (abs (- y median))))
-   0
-   numbers))
-
+(let* ((sorted (sort numbers <))
+       (median (list-ref sorted (floor/ (length numbers) 2)))
+       (part1
+        (foldl (lambda (x y) (+ x (abs (- y median))))
+               0
+               numbers)))
+  (format #t "part 1: ~A~%" part1))
 
 ; PART 2
 (define (triangular n) (/ (* n (+ n 1)) 2))
 
 (define (part2- avg)
-  (foldl
-   (lambda (x y) (+ x (triangular (abs (- y avg)))))
-   0
-   numbers))
+  (foldl (lambda (x y) (+ x (triangular (abs (- y avg)))))
+         0
+         numbers))
 
-(define avgCeil (ceiling/ (foldl + 0 numbers) (length numbers)))
-(define avgFloor (floor/ (foldl + 0 numbers) (length numbers)))
-
-(define (part2)
-  (min (part2- avgCeil) (part2- avgFloor)))
-
-
-(format #t "part 1: ~A~%" (part1))
-(format #t "part 2: ~A~%" (part2))
+(let* ((len (length numbers))
+       (sum (foldl + 0 numbers))
+       (avg-ceil (ceiling/ sum len))
+       (avg-floor (floor/ sum len))
+       (part2 (min (part2- avg-ceil) (part2- avg-floor))))
+  (format #t "part 2: ~A~%" part2))