diff --git a/docs/get-started/adding-custom-data.md b/docs/get-started/adding-custom-data.md
index c1ea0d6c0..6c4c4e2f4 100644
--- a/docs/get-started/adding-custom-data.md
+++ b/docs/get-started/adding-custom-data.md
@@ -26,7 +26,7 @@ const mapStyle = fromJS({
             source: 'points',
             paint: {
                 'circle-color': '#f00',
-                'circle-radius': '4'
+                'circle-radius': 4
             }
         }
     ]