diff --git a/module2/exo1/toy_notebook_en.ipynb b/module2/exo1/toy_notebook_en.ipynb
index 9b92b9be4940f5892266b6cadfceeb2b98cc4cbf..5cbade192be8cd788fdefae9f65c6e434413727a 100644
--- a/module2/exo1/toy_notebook_en.ipynb
+++ b/module2/exo1/toy_notebook_en.ipynb
@@ -8,7 +8,7 @@
     "\n",
     "March 28, 2019\n",
     "\n",
-    "# 1 On the computation of π\n",
+    "# 1 On the computation of $\\pi$\n",
     "\n",
     "## 1.1 Asking the maths library\n",
     "\n",
@@ -73,8 +73,8 @@
     "## 1.3 Using a surface fraction argument\n",
     "\n",
     "A method that is easier to understand and does not make use of the sin function is based on the\n",
-    "fact that if X ∼ U ( 0, 1 ) and Y ∼ U ( 0, 1 ) , then P [ X 2 + Y 2 ≤ 1 ] = π/4 (see (\"Monte Carlo method\"\n",
-    "on Wikipedia)[https://en.wikipedia.org/wiki/Monte_Carlo_method]). The following code uses this approach:"
+    "fact that if $X\\sim U(0,1)$ and $Y\\sim U(0,1)$ then $P[X^2+Y^2\\leq 1] = \\pi/4$  (see (\"[Monte Carlo method\"\n",
+    "on Wikipedia](https://en.wikipedia.org/wiki/Monte_Carlo_method)). The following code uses this approach:"
    ]
   },
   {
@@ -115,8 +115,8 @@
    "cell_type": "markdown",
    "metadata": {},
    "source": [
-    "It is then straightforward to obtain a (not really good) approximation to π by counting how\n",
-    "many times, on average, X 2 + Y 2 is smaller than 1:"
+    "It is then straightforward to obtain a (not really good) approximation to $\\pi$ by counting how\n",
+    "many times, on average, $X^2 + Y^2$ is smaller than 1:"
    ]
   },
   {