diff --git a/GitAssignmentObserver.iml b/GitAssignmentObserver.iml
new file mode 100644
index 0000000..26db12c
--- /dev/null
+++ b/GitAssignmentObserver.iml
@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <output url="file://$MODULE_DIR$/bin" />
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/src" isTestSource="false" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="inheritedJdk" />
+  </component>
+</module>
\ No newline at end of file
diff --git a/src/BallVolume.java b/src/BallVolume.java
new file mode 100644
index 0000000..33c90e5
--- /dev/null
+++ b/src/BallVolume.java
@@ -0,0 +1,13 @@
+
+public class BallVolume implements ISubscriber {
+
+	@Override
+	public void notifySubscriber(String input) {
+		
+                 double r=Double.parseDouble(input);
+                 double  volume= (4*22*r*r*r)/(3*7);
+ 
+                 System.out.println("Ball Volume is:" +volume);
+	}
+
+}
diff --git a/src/CircleArea.java b/src/CircleArea.java
new file mode 100644
index 0000000..2cab725
--- /dev/null
+++ b/src/CircleArea.java
@@ -0,0 +1,15 @@
+
+
+public class CircleArea implements ISubscriber {
+
+    
+    @Override
+	public void notifySubscriber(String input) {
+                double pi = 3.14 , res;
+                int r = Integer.parseInt(input);
+                res = pi *(r*r);
+		System.out.println("Area of circle:" + res );
+	}
+}
+    
+
diff --git a/src/CircleCircumference.java b/src/CircleCircumference.java
new file mode 100644
index 0000000..17a07e7
--- /dev/null
+++ b/src/CircleCircumference.java
@@ -0,0 +1,12 @@
+public class CircleCircumference implements ISubscriber
+{
+    @Override
+    public void notifySubscriber(String input)
+    {
+        Double radius = Double.parseDouble(input);
+        Double res = 2*Math.PI*radius;
+        System.out.println("circleCircumference is "+res );
+
+    }
+
+}
diff --git a/src/Fibonacci.java b/src/Fibonacci.java
new file mode 100644
index 0000000..6601e28
--- /dev/null
+++ b/src/Fibonacci.java
@@ -0,0 +1,22 @@
+public class Fibonacci implements ISubscriber 
+    {
+        public void notifySubscriber(String input)
+        {
+            int c=1,o=0,temp=0;
+            int f = Integer.parseInt(input);
+            
+            System.out.println(0);
+            System.out.println(1);
+            
+            while (c<f)
+            {
+                temp=c;
+                c=c+o;
+                o=temp;
+                System.out.println(c);
+                
+                
+            }
+            
+        }
+    }
\ No newline at end of file
diff --git a/src/LucasSeries.java b/src/LucasSeries.java
new file mode 100644
index 0000000..1e7a65c
--- /dev/null
+++ b/src/LucasSeries.java
@@ -0,0 +1,32 @@
+
+public class LucasSeries implements ISubscriber{
+
+    @Override
+    public void notifySubscriber(String input) {
+        try {
+            int n = Integer.parseInt(input);
+            for(int i=1;i<=n;i++)
+            {
+                System.out.print(printSeries(i)+" ");
+            }
+            System.out.println("");
+        } catch (NumberFormatException e) {
+            System.out.println("Enter a valid input");
+        }
+
+
+
+    }
+    public int printSeries(int input)
+    {
+        if(input==1||input==0)
+        {
+            return 2;
+        }
+        if(input==2)
+        {
+            return 1;
+        }
+        return printSeries(input-1)+printSeries(input-2);
+    }
+}
diff --git a/src/Main.java b/src/Main.java
index 9b8c2b0..f236cc3 100644
--- a/src/Main.java
+++ b/src/Main.java
@@ -1,17 +1,81 @@
 import java.util.Scanner;
 
 public class Main {
-	private static ISubscriber subscribers [] = {
-			new SimpleSubscriber(),
-			new ReallySimpleSubscriber(),
-	};
-	public static void main(String[] args) {
-		Topic mathTopic = new Topic();
-		for (ISubscriber sub : subscribers) {
-			mathTopic.addSubscriber(sub);
-		}
-		Scanner sc = new Scanner(System.in);
-		String input = sc.next();
-		mathTopic.dispatchEvent(input);
-	}
+    private static ISubscriber subscribers [] = {
+            new SimpleSubscriber(),
+            new ReallySimpleSubscriber(),
+            new MultiplicationSeries(),
+            new LucasSeries(),
+            new SphereVolume(),
+            new BallVolume(),
+	        new twoPowerN(),
+	        new CircleCircumference(),
+            new SphereArea(),
+       new CircleArea()
+
+            //please add your object here
+    };
+    public static void main(String[] args) {
+        Topic mathTopic = new Topic();
+        System.out.println("Enter 0 to execute all");
+        System.out.println("1-SimpleSubscriber\n" +
+                "2-ReallySimpleSubscriber\n3-MultiplicationSeries\n4-LucasSeries\n" +
+                "5-SphereVolume\n6-BallVolume\n7-twoPowerN\n8-CircleCircumference\n9-SphereArea\n10-CircleArea");
+        Scanner choice = new Scanner(System.in);
+        System.out.println("Enter your choice: ");
+        int c = choice.nextInt();
+        if(c==0) {
+
+            for (ISubscriber sub : subscribers) {
+                mathTopic.addSubscriber(sub);
+            }
+
+        }
+        else if(c==1)
+        {
+            mathTopic.addSubscriber(subscribers[0]);
+        }
+        else if(c==2)
+        {
+            mathTopic.addSubscriber(subscribers[1]);
+        }
+        else if(c==3)
+        {
+            mathTopic.addSubscriber(subscribers[2]);
+        }
+        else if(c==4)
+        {
+            mathTopic.addSubscriber(subscribers[3]);
+        }
+        else if(c==5)
+        {
+            mathTopic.addSubscriber(subscribers[4]);
+        }
+        else if(c==6)
+        {
+            mathTopic.addSubscriber(subscribers[5]);
+        }
+        else if(c==7)
+        {
+            mathTopic.addSubscriber(subscribers[6]);
+        }
+        else if(c==8) {
+            mathTopic.addSubscriber(subscribers[7]);
+        }
+        else if (c==9){
+            mathTopic.addSubscriber(subscribers[8]);
+        }
+	    else if (c==10){
+            mathTopic.addSubscriber(subscribers[9]);
+        }
+
+        //please call your method as the above calls here
+
+
+        Scanner sc = new Scanner(System.in);
+        System.out.println("Enter your input: ");
+        String input = sc.next();
+        mathTopic.dispatchEvent(input);
+
+    }
 }
diff --git a/src/MultiplicationSeries.java b/src/MultiplicationSeries.java
new file mode 100644
index 0000000..9ae55b8
--- /dev/null
+++ b/src/MultiplicationSeries.java
@@ -0,0 +1,31 @@
+
+
+
+public class MultiplicationSeries implements ISubscriber {
+    private int count;
+    private int product = 1;
+    @Override
+    public void notifySubscriber(String input) {
+        count = Integer.parseInt(input);
+        try {
+            System.out.println(MultSeries(count));
+        }
+        catch (NumberFormatException e) {
+            System.out.println(e.getMessage());
+        }
+
+    }
+    int MultSeries (int num)
+    {
+        int number = 1;
+        for (int i=0; i<num ; i++)
+        {
+            product*=number;
+            number++;
+        }
+        return product;
+    }
+}
+
+
+
diff --git a/src/SphereArea.java b/src/SphereArea.java
new file mode 100644
index 0000000..53c217e
--- /dev/null
+++ b/src/SphereArea.java
@@ -0,0 +1,7 @@
+public class SphereArea implements ISubscriber {
+    @Override
+    public void notifySubscriber(String input) {
+        int radius = Integer.parseInt(input);
+        System.out.println("The sphere area is "+4*radius*radius*3.14);
+    }
+}
diff --git a/src/SphereVolume.java b/src/SphereVolume.java
new file mode 100644
index 0000000..de06906
--- /dev/null
+++ b/src/SphereVolume.java
@@ -0,0 +1,10 @@
+public class SphereVolume implements ISubscriber
+{
+    @Override
+    public void notifySubscriber(String radius)
+    {
+        double Result =0.0;
+        Result = (Math.pow(Double.parseDouble(radius),3)*4/3*Math.PI); // pi = 22/7
+        System.out.println("The Sphere Volume --> "+Result);
+    }
+}
diff --git a/src/twoPowerN.java b/src/twoPowerN.java
new file mode 100644
index 0000000..7ce5a33
--- /dev/null
+++ b/src/twoPowerN.java
@@ -0,0 +1,12 @@
+public class twoPowerN implements ISubscriber
+{
+    @Override
+    public void notifySubscriber(String input) 
+    {	
+    	Double x = Double.parseDouble(input);
+    	Double result = Math.pow(2,x);
+    	System.out.println("2 Power "+x+" = "+result );
+
+    }
+   
+}