diff --git a/programming_exercise.ipynb b/programming_exercise.ipynb
index 8422efd..89d94db 100644
--- a/programming_exercise.ipynb
+++ b/programming_exercise.ipynb
@@ -1,49 +1,79 @@
 {
  "cells": [
+  {
+   "cell_type": "markdown",
+   "metadata": {},
+   "source": [
+    "# Jupyter Notebook demo\n",
+    "\n",
+    "Estimated workload for a standard MOOC, based on the number of weeks envisaged. \n",
+    "\n",
+    "**Instructions:**\n",
+    "\n",
+    "- Click on the code cell and press the play button (top menu)\n",
+    "- Choose the number of weeks in the below dropdown menu "
+   ]
+  },
   {
    "cell_type": "code",
-   "execution_count": 2,
+   "execution_count": 1,
    "metadata": {},
    "outputs": [
     {
-     "name": "stdout",
-     "output_type": "stream",
-     "text": [
-      "5\n"
-     ]
+     "data": {
+      "application/vnd.jupyter.widget-view+json": {
+       "model_id": "b258ef4693094d61ad81d42020ee3048",
+       "version_major": 2,
+       "version_minor": 0
+      },
+      "text/plain": [
+       "interactive(children=(Dropdown(description='Weeks', options=(3, 4, 5, 6), value=3), Output()), _dom_classes=('…"
+      ]
+     },
+     "metadata": {},
+     "output_type": "display_data"
     }
    ],
    "source": [
-    "print(2+3)"
+    "from ipywidgets import interact\n",
+    "from IPython.core.display import display, HTML\n",
+    "\n",
+    "def workload(Weeks):\n",
+    "    videos = Weeks*8 \n",
+    "    practice_quizzes = Weeks*8*5\n",
+    "    graded_quizzes = Weeks*10   \n",
+    "    display(HTML(\"<p></p><h2>Work load:</h2><ul><li>About <b>{} videos </b> of about 10 min. each <i>(about 8 videos per week) </i></li><li>About <b>{} practice quiz questions </b><i>(about 1 question per 2 min. of video, 40 questions per week)</i></li><li>About <b>{} graded quiz questions </b><i>(about 10 questions per week)</i></li></ul><p><b>We strongly recommand to replace groups of quiz questions by hands-on exercises.</b></p><h1> </h1>\".format(videos, practice_quizzes, graded_quizzes)))\n",
+    "    \n",
+    "result = interact(workload, Weeks=[3, 4, 5, 6])"
    ]
   },
   {
    "cell_type": "code",
    "execution_count": null,
    "metadata": {},
    "outputs": [],
    "source": []
   }
  ],
  "metadata": {
   "kernelspec": {
    "display_name": "Python 3",
    "language": "python",
    "name": "python3"
   },
   "language_info": {
    "codemirror_mode": {
     "name": "ipython",
     "version": 3
    },
    "file_extension": ".py",
    "mimetype": "text/x-python",
    "name": "python",
    "nbconvert_exporter": "python",
    "pygments_lexer": "ipython3",
    "version": "3.6.9"
   }
  },
  "nbformat": 4,
  "nbformat_minor": 4
 }