diff --git a/src/koans/04_sets.clj b/src/koans/04_sets.clj
index 0b5d14e..d6b4063 100644
--- a/src/koans/04_sets.clj
+++ b/src/koans/04_sets.clj
@@ -1,5 +1,6 @@
 (ns koans.04-sets
-  (:require [koan-engine.core :refer :all]))
+  (:require [koan-engine.core :refer :all]
+            [clojure.set :as set]))
 
 (meditations
   "You can create a set by converting another collection"
@@ -12,10 +13,10 @@
   (= __ (set '(1 1 2 2 3 3 4 4 5 5)))
 
   "You can ask clojure for the union of two sets"
-  (= __ (clojure.set/union #{1 2 3 4} #{2 3 5}))
+  (= __ (set/union #{1 2 3 4} #{2 3 5}))
 
   "And also the intersection"
-  (= __ (clojure.set/intersection #{1 2 3 4} #{2 3 5}))
+  (= __ (set/intersection #{1 2 3 4} #{2 3 5}))
 
   "But don't forget about the difference"
-  (= __ (clojure.set/difference #{1 2 3 4 5} #{2 3 5})))
+  (= __ (set/difference #{1 2 3 4 5} #{2 3 5})))