diff --git a/.obsidian/workspace.json b/.obsidian/workspace.json
index dca908b..745e8f7 100644
--- a/.obsidian/workspace.json
+++ b/.obsidian/workspace.json
@@ -18,21 +18,8 @@
                 "source": false
               }
             }
-          },
-          {
-            "id": "accf3e9b23e83334",
-            "type": "leaf",
-            "state": {
-              "type": "markdown",
-              "state": {
-                "file": "Algo/Courses/Chapter 6 - Lists (Exercises).md",
-                "mode": "source",
-                "source": false
-              }
-            }
           }
-        ],
-        "currentTab": 1
+        ]
       }
     ],
     "direction": "vertical"
@@ -169,10 +156,11 @@
       "command-palette:Open command palette": false
     }
   },
-  "active": "accf3e9b23e83334",
+  "active": "88e153f7ea61ad97",
   "lastOpenFiles": [
-    "Algo/Courses/Chapter 6 - Lists.md",
+    "Algo/Séminaire/Chapter 3 - Case analysis.md",
     "Algo/Courses/Chapter 6 - Lists (Exercises).md",
+    "Algo/Courses/Chapter 6 - Lists.md",
     "Algo/Courses",
     "Algo/Séminaire/Exercices seminaire.md",
     "Algo/CM/CM du 27 septembre.md",
@@ -193,7 +181,6 @@
     "COM-ADMR",
     "Methodologie",
     "Algo/Séminaire/Chapter 4 - A bit of imperative.md",
-    "Algo/Séminaire/Chapter 3 - Case analysis.md",
     "Algo/Séminaire/Introduction.md",
     "Algo/Séminaire/Chapter 1 - CAML basics.md",
     "Algo/Séminaire/assets/exception-meme.png",
diff --git a/Algo/Courses/Chapter 6 - Lists (Exercises).md b/Algo/Courses/Chapter 6 - Lists (Exercises).md
index d7eae56..7528ea6 100644
--- a/Algo/Courses/Chapter 6 - Lists (Exercises).md	
+++ b/Algo/Courses/Chapter 6 - Lists (Exercises).md	
@@ -11,9 +11,43 @@ let rec count x n =
 	if x = [] then
 		0
 	else
-		let e::t = x
+		let e::t = x in
 		if e = x then
 			1 + count t n
 		else
-			count t n
+			count t n;;
+```
+
+## 1.3 - Search
+```
+let rec search x n =
+	if x = [] then
+		0
+	else
+		let e::t = x in
+		if e = x then
+			true
+		else
+			search t n;;
+```
+
+## 1.4 - $n^{th}$
+```
+let rec length l = 
+	if l = [] then
+		0
+	else
+		let e::t = l in
+			1 + length t;;
+let rec nth x n =
+	if (x = [] || n =< 0) then
+		Invalid_arg "The number of element in the list is 0"
+	else if length x < n then
+		Failwith "The list is too short"
+	else
+		let e::t = x in
+		if e = x then
+			1 + count t n
+		else
+			count t n;;
 ```
\ No newline at end of file