diff --git a/Src/BootCamp.Chapter/BootCamp.Chapter.csproj b/Src/BootCamp.Chapter/BootCamp.Chapter.csproj
index 958d2f1da..fa2362844 100644
--- a/Src/BootCamp.Chapter/BootCamp.Chapter.csproj
+++ b/Src/BootCamp.Chapter/BootCamp.Chapter.csproj
@@ -2,7 +2,7 @@
 
   <PropertyGroup>
     <OutputType>Exe</OutputType>
-    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <TargetFramework>netcoreapp6.0</TargetFramework>
   </PropertyGroup>
 
 </Project>
diff --git a/Src/BootCamp.Chapter/Checks.cs b/Src/BootCamp.Chapter/Checks.cs
index 49864932a..0f6d1e241 100644
--- a/Src/BootCamp.Chapter/Checks.cs
+++ b/Src/BootCamp.Chapter/Checks.cs
@@ -16,26 +16,25 @@ public static class Checks
     {
         public static int PromptInt(string message)
         {
-            // To do: call your implementation. 
-            return 0;
+            return Lesson4.PromptInt(message);
+            
         }
 
         public static string PromptString(string message)
         {
-            // To do: call your implementation. 
-            return "";
+            return Lesson4.PromptString(message);
+            
         }
 
         public static float PromptFloat(string message)
         {
-            // To do: call your implementation. 
-            return 0;
+            return Lesson4.PromptFloat(message);
         }
 
         public static float CalculateBmi(float weight, float height)
         {
-            // To do: call your implementation. 
-            return 0;
+            return Lesson4.CalculateBMI(weight, height);
+            
         }
     }
 }
diff --git a/Src/BootCamp.Chapter/Lesson4.cs b/Src/BootCamp.Chapter/Lesson4.cs
new file mode 100644
index 000000000..686419ad5
--- /dev/null
+++ b/Src/BootCamp.Chapter/Lesson4.cs
@@ -0,0 +1,87 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.IO;
+
+namespace BootCamp.Chapter
+{
+    internal class Lesson4
+    {
+        public static void demo()
+        {
+            //Gather the input from the user.
+            string name = PromptString("Enter your name: ");
+            string surName = PromptString("Enter your surname: ");
+            int age = PromptInt("Enter your age: ");
+            float height = PromptFloat("Enter your height(m): ");
+            float weight = PromptFloat("Enter your waight(Kg): ");
+
+            //Find BMI
+            double bodyMassIndex = CalculateBMI(weight, height);
+            if(bodyMassIndex <= 0f ) 
+            {
+                return;
+            }
+            //Print messages
+            Console.WriteLine(name + " " + surName + " is " + age + " years old, his weight is " + weight + " kg and his height is " + height + "m.");
+            Console.WriteLine("Body Mass Index measured for " + name + " " + surName + " is " + bodyMassIndex);
+        }
+
+        public static float CalculateBMI(float weight, float height)
+        {
+            if(weight <= 0f || height <= 0f)
+            {
+                Console.WriteLine("Failed calculating BMI. Reason:");
+                if (height <= 0f) Console.WriteLine("Height cannot be equal or less than zero, but was " + height);
+                if (weight <= 0f) Console.WriteLine("Weight cannot be equal or less than zero, but was " + weight);
+                return -1f;
+            }
+            float bodyMassIndex = (weight / (height * height));
+            return bodyMassIndex;
+        }
+
+        public static int PromptInt(string Message)
+        {
+            int age;
+            Console.WriteLine(Message);
+            string Input = Console.ReadLine();
+            bool isAgeValid = int.TryParse(Input, out age);
+            if (!isAgeValid)
+            {
+                Console.Write("\"" + Input + "\" is not a valid number." + Environment.NewLine);
+                _ = Environment.NewLine;
+                return -1;
+            }
+            return age;
+
+        }
+
+        public static float PromptFloat(string Message)
+        {
+            float metrics;
+            Console.WriteLine(Message);
+            string Input = Console.ReadLine();
+            bool IsValidHeight_Weigth = float.TryParse(Input, NumberStyles.Float, NumberFormatInfo.InvariantInfo, out metrics);
+            if (!IsValidHeight_Weigth) 
+            {
+                Console.Write( "\"" + Input + "\" is not a valid number." + Environment.NewLine);
+               
+                return -1f;
+            }
+            return metrics;
+        }
+
+        public static string PromptString(string Message)
+        {
+            string Name;
+            Console.WriteLine(Message);
+            Name = Console.ReadLine();
+            if(!String.IsNullOrEmpty(Name)) return Name;
+            Console.WriteLine("Name cannot be empty" + Environment.NewLine);
+            return "-";
+        }
+    }
+}
diff --git a/Src/BootCamp.Chapter/Program.cs b/Src/BootCamp.Chapter/Program.cs
index 94e5531bc..09fa8183d 100644
--- a/Src/BootCamp.Chapter/Program.cs
+++ b/Src/BootCamp.Chapter/Program.cs
@@ -9,6 +9,7 @@ class Program
     {
         static void Main(string[] args)
         {
+            Lesson4.demo();
         }
     }
 }
diff --git a/Tests/BootCamp.Chapter.Tests/BootCamp.Chapter.Tests.csproj b/Tests/BootCamp.Chapter.Tests/BootCamp.Chapter.Tests.csproj
index 3a8778c77..ffca4abc4 100644
--- a/Tests/BootCamp.Chapter.Tests/BootCamp.Chapter.Tests.csproj
+++ b/Tests/BootCamp.Chapter.Tests/BootCamp.Chapter.Tests.csproj
@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <TargetFramework>netcoreapp6.0</TargetFramework>
 
     <IsPackable>false</IsPackable>
   </PropertyGroup>
diff --git a/Tests/BootCamp.Chapter.Tests/Utils/FakeConsole.cs b/Tests/BootCamp.Chapter.Tests/Utils/FakeConsole.cs
index 8a058c034..180e6adf7 100644
--- a/Tests/BootCamp.Chapter.Tests/Utils/FakeConsole.cs
+++ b/Tests/BootCamp.Chapter.Tests/Utils/FakeConsole.cs
@@ -30,4 +30,20 @@ public static void Cleanup(string testKey)
             File.Delete($"{testKey}.{TestFileExtension}");
         }
     }
+
+
+    public static class ConsoleStub
+    {
+        public static StringWriter StubConsole(string readLineReturn)
+            {
+                var output = new StringWriter();
+                Console.SetOut(output);
+
+                var input = new StringReader(readLineReturn);
+                Console.SetIn(input);
+
+                return output;
+            }
+    }
+    
 }