AYUDA URGENTE

Hola soy nueva en esto, les cuento e mirado y mirado este código y aun no se que esta mal, quizás esta bien casi todo pero hay que agregarle algo, ya tengo hecho el applets html.
gracias por su ayuda y que sigan con una feliz noche. Donde está el error?
import java.awt.*;
import java.applet.*;
import java.awt.event.*;
public class AppletEventos1 extends Applet implements ActionListener {

Label l1, l2, l3;
TextField t1, t2, t3;
Button b1, b2, b3, b4, b5, b6, b7, b8;

public AppletEventos1() {

l1 = new Label("numero");
l2 = new Label("numero2");
l3 = new Label("resultado");
t1 = new TextField();
t2 = new TextField();
t3 = new TextField();
b1 = new Button("suma");
b2 = new Button("resta");
b3 = new Button("multiplicar");
b4 = new Button("division");
b5 = new Button("raiz de 1");
b6 = new Button("raiz de 2");
b7 = new Button("mayor");
b8 = new Button("limpia");
add(l1);
add(t1);
add(l2);
add(t2);
add(l3);
add(t3);
add(b1);
add(b2);
add(b3);
add(b4);
add(b5);
add(b6);
add(b7);
add(b8);

b1. addActionListener(this);
b2. addActionListener(this);
b3. addActionListener(this);
b4. addActionListener(this);
b5. addActionListener(this);
b6. addActionListener(this);
b8. addActionListener(this);
b5. addActionListener(this);
}

public void actionPerformed(ActionEvent ae) {

if (ae.getSource() == b1){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int suma = 0;
suma =n+n2;
for(int i = 1; i<= n; i++){
suma +=i;
}
t3.setText("" + suma);
}
if (ae.getSource() == b2){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int resta = 0;
resta =n2-n;
for(int i = 1; i<= n; i++){
resta +=i;
}
t3.setText("" + resta);
}
if (ae.getSource() == b3){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int multiplicar = 0;
multiplicar =n*n2;
for(int i = 1; i<= n; i++){
multiplicar +=i;
}
t3.setText("" + multiplicar);
}
if (ae.getSource() == b4){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int division = 0;
division = n/n2;
for(int i = 1; i<= n; i++){
division +=i;
}
t3.setText("" + division);
}
if (ae.getSource() == b5){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int raiz1 = 0;
for(int i = 1; i<= n; i++){
raiz1 +=i;
}
t3.setText("" + raiz1);
}
if (ae.getSource() == b6){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int raiz2 = 0;
for(int i = 1; i<= n; i++){
raiz2 +=i;
}
t3.setText("" + raiz2);
}
if (ae.getSource() == b7){
int n = Integer.parseInt(t1.getText());
int n2 = Integer.parseInt(t2.getText());
int mayor = 0;
for(int i = 1; i<= n; i++){
mayor +=i;
}
t3.setText("" + mayor);
}
if (ae.getSource() == b8){
t1.setText("");
t2.setText("");
t3.setText("");
}

}
}