diff --git a/tutorials/performance/cpu_optimization.rst b/tutorials/performance/cpu_optimization.rst
index 933ad0729..485247220 100644
--- a/tutorials/performance/cpu_optimization.rst
+++ b/tutorials/performance/cpu_optimization.rst
@@ -101,7 +101,7 @@ the following:
     update_enemies()
 
     var time_end = Time.get_ticks_usec()
-    print("update_enemies() took %d microseconds" % time_end - time_start)
+    print("update_enemies() took %d microseconds" % (time_end - time_start))
 
  .. code-tab:: csharp