fix: fix typos

one_md_per_day_format/piscine/Week1/day1.md

@@ -404,7 +404,7 @@ This can be done in three steps: Get the max, create a boolean mask that indicat
 
 ---
 
-## Exercise 9 Football tournament
+# Exercise 9 Football tournament
 
 The goal of this exercise is to learn to use permutations, complex
 

one_md_per_day_format/piscine/Week1/day2.md

@@ -42,7 +42,7 @@ It contains ALL you need to know about Pandas.
 
   - https://jakevdp.github.io/PythonDataScienceHandbook/03.04-missing-values.html
 
-# Exercice 1
+# Exercice 1 Your first DataFrame
 
 The goal of this exercise is to learn to create basic Pandas objects.
 

one_md_per_day_format/piscine/Week1/day5.md

@@ -32,7 +32,7 @@ Pandas website
 - https://pandas.pydata.org/Pandas_Cheat_Sheet.pdf
 - https://www.learndatasci.com/tutorials/python-pandas-tutorial-complete-introduction-for-beginners/
 
-# Exercise 1
+# Exercise 1 Series
 
 The goal of this exercise is to learn to manipulate time series in Pandas.
 
@@ -80,7 +80,7 @@ The goal of this exercise is to learn to manipulate time series in Pandas.
 
     If the `NaN` values have been dropped the solution is also accepted. The solution uses `rolling().mean()`.
 
-# Exercise 2
+# Exercise 2 Financial data
 
 The goal of this exercise is to learn to use Pandas on Time Series an on Financial data.