diff --git a/01-Python_essentials.ipynb b/01-Python_essentials.ipynb
index fac1c24b37fb104a052e3b541c563000b1a78b09..d097f8345f7313046836af07427fba5ddf4885ff 100644
--- a/01-Python_essentials.ipynb
+++ b/01-Python_essentials.ipynb
@@ -5,7 +5,7 @@
    "id": "66ce7a2d-ac19-4dbf-9690-e6ccfe41b4cf",
    "metadata": {},
    "source": [
-    "# Python and notebook basics\n",
+    "# 1. Python and notebook basics\n",
     "\n",
     "In this first chapter, we will cover the very essentials of Python and notebooks such as creating a variable, importing packages, using functions, seeing how variables behave in the notebook etc. We will see more details on some of these topics, but this very short introduction will then allow us to quickly dive into more applied and image processing specific topics without having to go through a full Python introduction."
    ]