diff --git a/old_projects/number_line_scene.py b/old_projects/number_line_scene.py
index 88303a72..6bee856a 100644
--- a/old_projects/number_line_scene.py
+++ b/old_projects/number_line_scene.py
@@ -1,3 +1,5 @@
+import numpy as np
+
 class NumberLineScene(Scene):
     def construct(self, **number_line_config):
         self.number_line = NumberLine(**number_line_config)