Add,Subtract,Multiply,Divide two number in Java

import java.awt.*;
import java.awt.event.*;
class IFrame extends Frame
{
Label l1;
Label l2;
Label l3;
Label l5;
Label l6;
final TextField t1;
final TextField t2;
final TextField t3;
IFrame()
{ 
super("IDE to Add Values");
setSize(500,300);
setVisible(true);
setBackground(Color.ORANGE);
Panel p=new Panel();
l1=new Label("Enter first Value");
l2=new Label("Enter second Value");
l3=new Label("RESULT");
l5=new Label(" ");
l6=new Label(" ");
t1=new TextField(5);
t2=new TextField(5);
t3=new TextField(5);
Button b1=new Button("CLOSE");
Button b2=new Button("ADD");
Button b3=new Button("SUBTRACT");
Button b4=new Button("MULTIPLY");
Button b5=new Button("DIVIDE");
Button b6=new Button("CLEAR");
p.setLayout(new GridLayout(7,2));
p.add(l1);
p.add(t1);
p.add(l2);
p.add(t2);
p.add(l3);
p.add(t3);
p.add(b2);
p.add(b1);
p.add(b3);
p.add(b6);
p.add(b4);
p.add(l5);
p.add(b5);
p.add(l6);
add(p,BorderLayout.CENTER);
b1.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
System.exit(0);
}});
b2.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
String s1=t1.getText();
String s2=t2.getText();
int x=Integer.parseInt(s1);
int y=Integer.parseInt(s2);
int z=x+y;
String s3=" "+z;
t3.setText(s3);
((Component)e.getSource()).setBackground(Color.PINK);
}});
b3.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
String s1=t1.getText();
String s2=t2.getText();
int x=Integer.parseInt(s1);
int y=Integer.parseInt(s2);
int z=x-y;
String s3=" "+z;
t3.setText(s3);
((Component)e.getSource()).setBackground(Color.GREEN);
}});
b4.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
String s1=t1.getText();
String s2=t2.getText();
int x=Integer.parseInt(s1);
int y=Integer.parseInt(s2);
int z=x*y;
String s3=" "+z;
t3.setText(s3);
((Component)e.getSource()).setBackground(Color.GREEN);
}});
b5.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
String s1=t1.getText();
String s2=t2.getText();
int x=Integer.parseInt(s1);
int y=Integer.parseInt(s2);
int z=x/y;
String s3=" "+z;
t3.setText(s3);
((Component)e.getSource()).setBackground(Color.GREEN);
}});
/*b6.addMouseListener(new MouseAdapter()
{
public void mouseClicked(MouseEvent e)
{
String s1=t1.getText();
String s2=t2.getText();
t1.setText(NULL);
t2.setText(NULL);
t3.setText(NULL);
((Component)e.getSource()).setBackground(Color.GREEN);
}});*/
}}
class calculator
{
public static void main(String as[])
{
IFrame f=new IFrame();
}}