... Rectangle(1 20, 1 50, 2 50, 30) ); this.getContentPane().add(khung); btchao.setBackground(Color.yellow); btchao.setOpaque(true); btchao.setBounds(new Rectangle( 100 , 200 , 80, 30) ); btchao.setText("Chao"); ... Rectangle(1 90, 60, 1 30, 30) ); tieude.setText(" Cac Phep Tinh Co Ban& quot;); this.getContentPane().add(tieude); // He so 1 www.tamga.tk so1.setBounds(new Rectangle( 90, 1 10, 1 40, 30) ); so1.setText("Nhap ... ketqua.setBounds(new Rectangle( 90, 1 50, 1 40, 30) ); ketqua.setText("Ket qua :"); this.getContentPane().add(ketqua); khungketqua.setBounds(new Rectangle(1 50, 155, 200 , 20) ); this.getContentPane().add(khungketqua);...