diff --git a/lecture-material/11-Web_1/11-web.ipynb b/lecture-material/11-Web_1/11-web.ipynb
index 26c8d9b297a95f6a6821c6d2e7fd6153db869447..e0ea5ee84cf33002214c57df631ea3a3e55fe127 100644
--- a/lecture-material/11-Web_1/11-web.ipynb
+++ b/lecture-material/11-Web_1/11-web.ipynb
@@ -367,7 +367,7 @@
    "metadata": {},
    "source": [
     "### Combining taking screenshot and displaying it\n",
-    "- useful for p3"
+    "- useful for p4"
    ]
   },
   {
diff --git a/lecture-material/11-Web_1/11-web_001.ipynb b/lecture-material/11-Web_1/11-web_001.ipynb
index 484ce6ee3dee8f0df2535d48d9fcd9313124efd0..5f3fc54af8c5f2692c59f3858d9ce48e19f0113b 100644
--- a/lecture-material/11-Web_1/11-web_001.ipynb
+++ b/lecture-material/11-Web_1/11-web_001.ipynb
@@ -204,7 +204,7 @@
    "metadata": {},
    "source": [
     "### Combining taking screenshot and displaying it\n",
-    "- useful for p3"
+    "- useful for p4"
    ]
   },
   {
diff --git a/lecture-material/11-Web_1/11-web_002.ipynb b/lecture-material/11-Web_1/11-web_002.ipynb
index 484ce6ee3dee8f0df2535d48d9fcd9313124efd0..5f3fc54af8c5f2692c59f3858d9ce48e19f0113b 100644
--- a/lecture-material/11-Web_1/11-web_002.ipynb
+++ b/lecture-material/11-Web_1/11-web_002.ipynb
@@ -204,7 +204,7 @@
    "metadata": {},
    "source": [
     "### Combining taking screenshot and displaying it\n",
-    "- useful for p3"
+    "- useful for p4"
    ]
   },
   {