diff --git a/.vscode/settings.json b/.vscode/settings.json
index daab734..1c0f27b 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -1,6 +1,6 @@
 {
     "dotnet.defaultSolution": "FirstProject.sln",
-    "editor.fontSize": 14,
+    "editor.fontSize": 20,
     "window.zoomLevel": 1,
     "terminal.integrated.fontSize": 14,
     "workbench.tree.indent": 23
diff --git a/Algorithms/Exercices1.cs b/Algorithms/Exercices1.cs
new file mode 100644
index 0000000..39dd9c5
--- /dev/null
+++ b/Algorithms/Exercices1.cs
@@ -0,0 +1,37 @@
+namespace Algorithms;
+using System;
+using Algorithms.NumberTheory;
+
+class SolutionExercices1 {
+
+    public static string removeTitle(string header)
+    {
+        int idx = header.IndexOf(".");
+        return header.Substring(idx + 1);
+    }
+
+    public static void printEachDirectoryOnPath(string path)
+    {
+        string[] subs = path.Split(':');
+
+        foreach (var sub in subs)
+        {
+            Console.WriteLine(sub);
+        }
+    }
+
+    public static void Main_(String[] args){
+        // {titre}.{sous-titre}.{sous-sous- titre}
+        // 4.56.2 -> 56.2
+        // 4.b.ii  -> b.ii
+        string header = "4.56.2";
+        Console.WriteLine(removeTitle("4.56.2")); // "56.2"
+        Console.WriteLine(removeTitle("4.b.ii")); // "b.ii"
+        Console.WriteLine(removeTitle("")); // ""
+        Console.WriteLine(removeTitle("4.b")); // "b"
+
+
+        string? path = Environment.GetEnvironmentVariable("PATH");
+        printEachDirectoryOnPath(path ?? "");
+    }
+}
\ No newline at end of file
diff --git a/Algorithms/NumberTheory/Simple.cs b/Algorithms/NumberTheory/Simple.cs
new file mode 100644
index 0000000..ccbd563
--- /dev/null
+++ b/Algorithms/NumberTheory/Simple.cs
@@ -0,0 +1,15 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Algorithms.NumberTheory;
+
+class Simple
+{
+    internal double d;
+
+    public Simple(double d) {
+        this.d = d;
+    }
+}
diff --git a/Algorithms/Point.cs b/Algorithms/Point.cs
new file mode 100644
index 0000000..8c65485
--- /dev/null
+++ b/Algorithms/Point.cs
@@ -0,0 +1,64 @@
+namespace Algorithms;
+using System;
+
+
+class Point
+{
+
+    private double x;
+    private double y;
+
+    public Point(double x, double y)
+    {
+        this.x = x;
+        this.y = y;
+    }
+
+    public double X()
+    {
+        return x;
+    }
+
+    public double Y()
+    {
+        return y;
+    }
+
+    public double Distance()
+    {
+        return Math.Sqrt(X() * X() + Y() * Y());
+    }
+
+}
+
+class Point2
+{
+
+    private double x;
+    private double y;
+
+    public Point2(double x, double y)
+    {
+        this.x = x;
+        this.y = y;
+    }
+
+    public double X
+    {
+        get => x;
+        set => x = value;
+    }
+}
+
+
+class Manager
+{
+    internal string name;
+    private int level;
+
+    public Manager(string name, int level){
+        this.name = name;
+        this.level = level;
+    }
+   
+}
\ No newline at end of file
diff --git a/Algorithms/Program.cs b/Algorithms/Program.cs
index f8f3751..5f3d54f 100644
--- a/Algorithms/Program.cs
+++ b/Algorithms/Program.cs
@@ -1,26 +1,28 @@
 // See https://aka.ms/new-console-template for more information
 namespace Algorithms;
 using System;
+using Algorithms.NumberTheory;
 
-class Point{
-    
-    private double x;
-    private double y;
-    
-    public Point(double x, double y){
-        this.x = x;
-        this.y = y;
+class Program
+{
+
+    public static void printEachDirectoryOnPath(string path)
+    {
+        string[] subs = path.Split(':');
+
+        foreach (var sub in subs)
+        {
+            Console.WriteLine(sub);
+        }
     }
-    
-    public double Distance(){
-        return Math.Sqrt(x * x + x * y);
-    }
-}
 
 
-class Foo{
-    public static void Main(String[] args){
-        Point p = new Point(3, 4);
-        Console.WriteLine("Hello World From A Class: " + p.Distance());
+    public static void Main(String[] args)
+    {
+        Point point = new Point(0, 0);
+        Point point2 = new Point(10, 10);
+        Console.WriteLine("La valeure de X de point est: " + point.X());
+        Console.WriteLine("La valeure de X de point2 est: " + point2.X());
+
     }
 }
diff --git a/Algorithms/TrigonometryUtil.cs b/Algorithms/TrigonometryUtil.cs
new file mode 100644
index 0000000..4aceaf8
--- /dev/null
+++ b/Algorithms/TrigonometryUtil.cs
@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Algorithms;
+
+
+class TrigonometryUtil {
+
+    public static double Side(double hypothenuse, double otherSide){
+        return Math.Sqrt(hypothenuse * hypothenuse  -  otherSide * otherSide);
+    }
+
+    public static double Hypothenuse(double a, double b){
+        return Math.Sqrt(a * a + b * b);
+    }
+
+    public static double Area(double hypothenuse, double side){
+        double otherSide = Side(hypothenuse, side);
+        return side * otherSide * 0.5;
+    }
+}
\ No newline at end of file