diff --git a/docs/haku.dj b/docs/haku.dj
index aa93e43..b371d88 100644
--- a/docs/haku.dj
+++ b/docs/haku.dj
@@ -394,7 +394,7 @@ If you'd like to reference a built-in function to e.g. pass it to a list-transfo
 
 ```haku
 add: \x, y -> x + y
-sum: [1, 2, 3] |reduce 0 sum
+sum: [1, 2, 3] |reduce 0 add
 
 sin': \x -> sin x
 sines: [0, pi*1/2, pi*2/2, pi*3/2] |map sin'