diff --git a/subjects/interpolation/README.md b/subjects/interpolation/README.md
index 550d7a2c..fc62eaf8 100644
--- a/subjects/interpolation/README.md
+++ b/subjects/interpolation/README.md
@@ -10,7 +10,7 @@ For each interpolation point, you must call the `callback` function with an arra
 - `x`: distance
 - `y`: point
 
-There should be a delay between each `callback` invocation; of `duration / step`, so that the final call happens after `duration`.
+There should be a delay between each `callback` invocation of `duration / step`, so that the final call happens after `duration`.
 
 ### Example