diff --git a/Src/BootCamp.Chapter/Checks.cs b/Src/BootCamp.Chapter/Checks.cs
index 49864932a..bce30fb48 100644
--- a/Src/BootCamp.Chapter/Checks.cs
+++ b/Src/BootCamp.Chapter/Checks.cs
@@ -17,25 +17,25 @@ public static class Checks
         public static int PromptInt(string message)
         {
             // To do: call your implementation. 
-            return 0;
+            return Lesson4.GetInt(message);
         }
 
         public static string PromptString(string message)
         {
             // To do: call your implementation. 
-            return "";
+            return Lesson4.GetString(message);
         }
 
         public static float PromptFloat(string message)
         {
             // To do: call your implementation. 
-            return 0;
+            return Lesson4.GetFloat(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..098a5aad0
--- /dev/null
+++ b/Src/BootCamp.Chapter/Lesson4.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Text;
+
+namespace BootCamp.Chapter
+{
+    public class Lesson4
+    {
+        public static void Demo()
+        {
+            var userOne = GetUserInfo();
+            Console.WriteLine($"{userOne}");
+
+            var userTwo = GetUserInfo();
+            Console.WriteLine($"{userTwo}");
+        }
+
+        public static string GetInput(string message)
+        {
+            Console.Write($"{message}");
+            var input = Console.ReadLine();
+            return input;
+        }
+
+        public static string GetString(string message)
+        {
+            var input = GetInput(message);
+            if (string.IsNullOrEmpty(input))
+            {
+                Console.WriteLine("Name cannot be empty");
+                return "-";
+            }
+            return input;
+        }
+        public static int GetInt(string message)
+        {
+            var input = GetInput(message);
+            var isValidNumber = int.TryParse(input, out var result);
+            return isValidNumber ? result : PrintAndReturnNumberError($"\"{input}\" is not a valid number.");
+
+        }
+        public static float GetFloat(string message)
+        {
+            var input = GetInput(message);
+            var isValidNumber = float.TryParse(input, NumberStyles.Float, CultureInfo.InvariantCulture, out var result);
+
+            return isValidNumber ? result : PrintAndReturnNumberError($"\"{input}\" is not a valid number.");
+        }
+
+        public static int PrintAndReturnNumberError(string message)
+        {
+            Console.WriteLine($"{message}");
+            return -1;
+        }
+
+        public static float CalculateBMI(float weight, float height)
+        {
+            if (weight <= 0 || height <= 0)
+            {
+                Console.WriteLine("Failed calculating BMI. Reason: ");
+                if (height <= 0)
+                    Console.WriteLine($"Height cannot be equal or less than zero, but was {height}.");
+                if (weight <= 0)
+                    Console.WriteLine($"Weight cannot be equal or less than zero, but was {weight}.");
+                return -1;
+            }
+
+            return weight / (float)Math.Pow(height, 2);
+        }
+
+        public static string GetUserInfo()
+        {
+            var name = GetInput("name: ");
+            var surName = GetInput("surname: ");
+            var age = GetInt("age: ");
+            var weight = GetFloat("weight: ");
+            var height = GetFloat("height: ");
+            var bmi = CalculateBMI(weight, height);
+
+            return PrintUserInfo(name, surName, age, weight, height);
+        }
+
+        public static string PrintUserInfo(string name, string sureName, int age, float weight, double height)
+        {
+            return $"{name} {sureName} is {age} years old, his weight is {weight} kg and his height is {height} cm.";
+        }
+    }
+}
diff --git a/Src/BootCamp.Chapter/Program.cs b/Src/BootCamp.Chapter/Program.cs
index 94e5531bc..9a916053f 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();
         }
     }
 }