diff --git a/topics/number_line.py b/topics/number_line.py
index 479805b3..6f56af6f 100644
--- a/topics/number_line.py
+++ b/topics/number_line.py
@@ -337,7 +337,7 @@ class NumberPlane(VMobject):
         return self
 
     def apply_function(self, function, maintain_smoothness = True):
-        SVGMobject.apply_function(self, function, maintain_smoothness = maintain_smoothness)
+        VMobject.apply_function(self, function, maintain_smoothness = maintain_smoothness)