diff --git a/9.rkt b/9.rkt
new file mode 100644
index 0000000..34e5a23
--- /dev/null
+++ b/9.rkt
@@ -0,0 +1,44 @@
+#lang curly-fn racket
+
+(require "scripts/aoc.rkt")
+
+;; solution for day 9
+
+;; helper functions here
+
+(define (part1 input)
+  (define vec (list->vector input))
+  (let/ec exit
+    (for ([i (in-range 25 (vector-length vec))])
+      (define valid?
+        (for*/first ([a (in-range (- i 25) i)] [b (in-range a i)]
+                     #:when (= (vector-ref vec i) (+ (vector-ref vec a) (vector-ref vec b)))) #t))
+      (unless valid?
+        (exit (vector-ref vec i))))))
+
+(define (part2 input)
+  (define pt1 10884537)
+  (define pt1-i 501)
+  (let/ec exit
+    (define vec (list->vector input))
+    (define (cb args)
+      (when (= pt1 (apply + args))
+        (exit (+ (apply min args) (apply max args)))))
+    (for* ([ct (in-range 3 100)] [i (in-range 0 (- pt1-i ct))])
+      (define sub (vector-copy vec i (+ i ct)))
+      (cb (vector->list sub)))))
+
+(module+ test
+  (require rackunit)
+  ;; tests here
+  (displayln "no tests :("))
+
+(module+ main
+  (define input (file->list "inputs/9"))
+  ;; part 1
+  (answer 9 1 (part1 input))
+
+  ;; part 2
+  (answer 9 2 (part2 input))
+
+  (displayln "meow"))