diff --git a/Activity_3_python/exercise_1/exercise_1_2.py b/Activity_3_python/exercise_1/exercise_1_2.py
deleted file mode 100644
index 7ee508a..0000000
--- a/Activity_3_python/exercise_1/exercise_1_2.py
+++ /dev/null
@@ -1,5 +0,0 @@
-cle = 1891126108268
-
-res = 97 - cle%97
-
-print("La clé de contrçôle de", cle, "est", res)
\ No newline at end of file
diff --git a/Activity_3_python/exercise_1/exercise_1_1.py b/Activity_3_python/exercises_1/exercise_1_1.py
similarity index 82%
rename from Activity_3_python/exercise_1/exercise_1_1.py
rename to Activity_3_python/exercises_1/exercise_1_1.py
index d912c69..0166887 100644
--- a/Activity_3_python/exercise_1/exercise_1_1.py
+++ b/Activity_3_python/exercises_1/exercise_1_1.py
@@ -5,7 +5,7 @@
 bool = True
 while bool:
    try:
-      fichier = int(input("What is the size of your file in kio ? "))
+      fichier = int(input("What is the size of your file in kio? "))
       print("Fichier :", fichier, "kio", "=", fichier * 2**10, "octets", "=", fichier * 8 * 2**10, "bits")
       bool = False
    except:
diff --git a/Activity_3_python/exercises_1/exercise_1_2.py b/Activity_3_python/exercises_1/exercise_1_2.py
new file mode 100644
index 0000000..9da8bcc
--- /dev/null
+++ b/Activity_3_python/exercises_1/exercise_1_2.py
@@ -0,0 +1,18 @@
+# The social security number is made up of 13 digits plus the control key (2 digits).
+# Example: 1 89 11 26 108 268 91
+# The control key is calculated using the formula :
+# Key = 97 - (social security number modulo 97)
+# Find the control key for your social security number.
+# Why use the control key?
+
+bool = True
+while bool:
+   try:
+      cle = int(input("What is your control key? "))
+      res = 97 - cle%97
+      print("The control key for", cle, "is", res)
+      bool = False
+   except:
+      print("You had to enter a key. Example: 1891126108268")
+
+# The purpose of the control key is to verify the validity of the social security number.f
\ No newline at end of file
diff --git a/Activity_3_python/exercise_1/exercise_1_3.py b/Activity_3_python/exercises_1/exercise_1_3.py
similarity index 100%
rename from Activity_3_python/exercise_1/exercise_1_3.py
rename to Activity_3_python/exercises_1/exercise_1_3.py
diff --git a/Activity_3_python/exercise_1/exercise_1_4.py b/Activity_3_python/exercises_1/exercise_1_4.py
similarity index 100%
rename from Activity_3_python/exercise_1/exercise_1_4.py
rename to Activity_3_python/exercises_1/exercise_1_4.py
diff --git a/Activity_3_python/exercise_1/exercise_1_5.py b/Activity_3_python/exercises_1/exercise_1_5.py
similarity index 100%
rename from Activity_3_python/exercise_1/exercise_1_5.py
rename to Activity_3_python/exercises_1/exercise_1_5.py
diff --git a/Activity_3_python/exercise_1/exercise_1_6.py b/Activity_3_python/exercises_1/exercise_1_6.py
similarity index 100%
rename from Activity_3_python/exercise_1/exercise_1_6.py
rename to Activity_3_python/exercises_1/exercise_1_6.py
diff --git a/Activity_3_python/exercise_1/exercise_1_6_mieux.py b/Activity_3_python/exercises_1/exercise_1_6_mieux.py
similarity index 100%
rename from Activity_3_python/exercise_1/exercise_1_6_mieux.py
rename to Activity_3_python/exercises_1/exercise_1_6_mieux.py
diff --git a/Activity_3_python/exercise_2/exercise_2_1.py b/Activity_3_python/exercises_2/exercise_2_1.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_1.py
rename to Activity_3_python/exercises_2/exercise_2_1.py
diff --git a/Activity_3_python/exercise_2/exercise_2_2_1.py b/Activity_3_python/exercises_2/exercise_2_2_1.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_2_1.py
rename to Activity_3_python/exercises_2/exercise_2_2_1.py
diff --git a/Activity_3_python/exercise_2/exercise_2_2_2.py b/Activity_3_python/exercises_2/exercise_2_2_2.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_2_2.py
rename to Activity_3_python/exercises_2/exercise_2_2_2.py
diff --git a/Activity_3_python/exercise_2/exercise_2_3.py b/Activity_3_python/exercises_2/exercise_2_3.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_3.py
rename to Activity_3_python/exercises_2/exercise_2_3.py
diff --git a/Activity_3_python/exercise_2/exercise_2_4.py b/Activity_3_python/exercises_2/exercise_2_4.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_4.py
rename to Activity_3_python/exercises_2/exercise_2_4.py
diff --git a/Activity_3_python/exercise_2/exercise_2_5.py b/Activity_3_python/exercises_2/exercise_2_5.py
similarity index 100%
rename from Activity_3_python/exercise_2/exercise_2_5.py
rename to Activity_3_python/exercises_2/exercise_2_5.py
diff --git a/Activity_3_python/exercise_3/exercise_3_1.py b/Activity_3_python/exercises_3/exercise_3_1.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_1.py
rename to Activity_3_python/exercises_3/exercise_3_1.py
diff --git a/Activity_3_python/exercise_3/exercise_3_2.py b/Activity_3_python/exercises_3/exercise_3_2.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_2.py
rename to Activity_3_python/exercises_3/exercise_3_2.py
diff --git a/Activity_3_python/exercise_3/exercise_3_3_1.py b/Activity_3_python/exercises_3/exercise_3_3_1.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_3_1.py
rename to Activity_3_python/exercises_3/exercise_3_3_1.py
diff --git a/Activity_3_python/exercise_3/exercise_3_3_2.py b/Activity_3_python/exercises_3/exercise_3_3_2.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_3_2.py
rename to Activity_3_python/exercises_3/exercise_3_3_2.py
diff --git a/Activity_3_python/exercise_3/exercise_3_4.py b/Activity_3_python/exercises_3/exercise_3_4.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_4.py
rename to Activity_3_python/exercises_3/exercise_3_4.py
diff --git a/Activity_3_python/exercise_3/exercise_3_5.py b/Activity_3_python/exercises_3/exercise_3_5.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_5.py
rename to Activity_3_python/exercises_3/exercise_3_5.py
diff --git a/Activity_3_python/exercise_3/exercise_3_6_1.py b/Activity_3_python/exercises_3/exercise_3_6_1.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_6_1.py
rename to Activity_3_python/exercises_3/exercise_3_6_1.py
diff --git a/Activity_3_python/exercise_3/exercise_3_6_2.py b/Activity_3_python/exercises_3/exercise_3_6_2.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_6_2.py
rename to Activity_3_python/exercises_3/exercise_3_6_2.py
diff --git a/Activity_3_python/exercise_3/exercise_3_7.py b/Activity_3_python/exercises_3/exercise_3_7.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_7.py
rename to Activity_3_python/exercises_3/exercise_3_7.py
diff --git a/Activity_3_python/exercise_3/exercise_3_8.py b/Activity_3_python/exercises_3/exercise_3_8.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_8.py
rename to Activity_3_python/exercises_3/exercise_3_8.py
diff --git a/Activity_3_python/exercise_3/exercise_3_9_1.py b/Activity_3_python/exercises_3/exercise_3_9_1.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_9_1.py
rename to Activity_3_python/exercises_3/exercise_3_9_1.py
diff --git a/Activity_3_python/exercise_3/exercise_3_9_2.py b/Activity_3_python/exercises_3/exercise_3_9_2.py
similarity index 100%
rename from Activity_3_python/exercise_3/exercise_3_9_2.py
rename to Activity_3_python/exercises_3/exercise_3_9_2.py