diff --git a/lib/koans/09_map_sets.ex b/lib/koans/09_map_sets.ex
index b40cca5..e851900 100644
--- a/lib/koans/09_map_sets.ex
+++ b/lib/koans/09_map_sets.ex
@@ -56,10 +56,6 @@ defmodule MapSets do
     assert MapSet.member?(modified_set, 1) == ___
   end
 
-  koan "How large is my map set?" do
-    assert MapSet.size(@set) == ___
-  end
-
   koan "Are these maps twins?" do
     new_set = MapSet.new([1, 2, 3])
 
diff --git a/test/koans/map_sets_koans_test.exs b/test/koans/map_sets_koans_test.exs
index ec6f134..886fb41 100644
--- a/test/koans/map_sets_koans_test.exs
+++ b/test/koans/map_sets_koans_test.exs
@@ -11,7 +11,6 @@ defmodule MapSetsTest do
       {:multiple, [true, false]},
       true,
       false,
-      5,
       false,
       true,
       7,