diff --git a/chapters/13/1/Percentiles.ipynb b/chapters/13/1/Percentiles.ipynb
index 8e54eed4..a364b997 100644
--- a/chapters/13/1/Percentiles.ipynb
+++ b/chapters/13/1/Percentiles.ipynb
@@ -16,6 +16,11 @@
     "In this section, we will give a definition that works consistently for all ranks and all lists."
    ]
   },
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": []
+  },
   {
    "cell_type": "code",
    "execution_count": 1,
@@ -94,7 +99,7 @@
    "metadata": {},
    "source": [
     "## The `percentile` function\n",
-    "The `percentile` function takes two arguments: a rank between 0 and 100, and a array. It returns the corresponding percentile of the array."
+    "The `percentile` function takes two arguments: a rank between 0 and 100, and an array. It returns the corresponding percentile of the array."
    ]
   },
   {