Calculator now with a GUI

import javax.swing.*;
import java.awt.Dimension;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
@SuppressWarnings("serial")
public class MathGUI extends JFrame{
    public String opreator;
    private JTextArea textOut;
    private JLabel lblError;
    public MathGUI() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setTitle("Calculator");
        getContentPane().setLayout(null);

        textOut = new JTextArea();
        textOut.setBounds(6, 6, 318, 105);
        getContentPane().add(textOut);

        JButton btnPlus = new JButton("+");
        btnPlus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                opreator = "+";
                try {
                    String FirstNumberString = txtFirstNumber.getText();
                    int FirstNumber = Integer.parseInt(FirstNumberString);
                    String SecondNumberString = txtSecondNumber.getText();
                    int SecondNumber = Integer.parseInt(SecondNumberString);
                    doMath(FirstNumber, opreator, SecondNumber);
                    textOut.setText("Answer: " + Final);
                } catch (Exception ex) {
                    lblError.setText("Please use small numbers");
                }
            }
        });
        btnPlus.setBounds(207, 123, 117, 29);
        getContentPane().add(btnPlus);

        JButton btnMinus = new JButton("-");
        btnMinus.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                opreator = "-";
                try {
                String FirstNumberString = txtFirstNumber.getText();
                int FirstNumber = Integer.parseInt(FirstNumberString);
                String SecondNumberString = txtSecondNumber.getText();
                int SecondNumber = Integer.parseInt(SecondNumberString);
                doMath(FirstNumber, opreator, SecondNumber);
                textOut.setText("Answer: " + Final);
                } catch (Exception ey) {
                    lblError.setText("Please use small numbers");
                }
            }
        });
        btnMinus.setBounds(207, 164, 117, 29);
        getContentPane().add(btnMinus);

        JButton btnMutiply = new JButton("*");
        btnMutiply.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                opreator = "*";
                try {
                String FirstNumberString = txtFirstNumber.getText();
                int FirstNumber = Integer.parseInt(FirstNumberString);
                String SecondNumberString = txtSecondNumber.getText();
                int SecondNumber = Integer.parseInt(SecondNumberString);
                doMath(FirstNumber, opreator, SecondNumber);
                textOut.setText("Answer: " + Final);
                } catch (Exception ez) {
                    lblError.setText("Please use small numbers");
                }
            }
        });
        btnMutiply.setBounds(207, 205, 117, 29);
        getContentPane().add(btnMutiply);

        JButton btnDivide = new JButton("/");
        btnDivide.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                opreator = "/";
                try {
                String FirstNumberString = txtFirstNumber.getText();
                int FirstNumber = Integer.parseInt(FirstNumberString);
                String SecondNumberString = txtSecondNumber.getText();
                int SecondNumber = Integer.parseInt(SecondNumberString);
                doMath(FirstNumber, opreator, SecondNumber);
                textOut.setText("Answer: " + Final);
                } catch (Exception ea) {
                    lblError.setText("Please use small numbers");
                }
            }
        });
        btnDivide.setBounds(207, 246, 117, 29);
        getContentPane().add(btnDivide);

        JButton btnPercentage = new JButton("%");
        btnPercentage.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent e) {
                opreator = "%";
                try {
                String FirstNumberString = txtFirstNumber.getText();
                int FirstNumber = Integer.parseInt(FirstNumberString);
                String SecondNumberString = txtSecondNumber.getText();
                int SecondNumber = Integer.parseInt(SecondNumberString);
                doMath(FirstNumber, opreator, SecondNumber);
                textOut.setText("Answer: " + Final);
                } catch (Exception eb) {
                    lblError.setText("Please use small numbers");
                }
            }
        });
        btnPercentage.setBounds(207, 287, 117, 29);
        getContentPane().add(btnPercentage);

        txtFirstNumber = new JTextField();
        txtFirstNumber.setBounds(89, 123, 117, 26);
        getContentPane().add(txtFirstNumber);
        txtFirstNumber.setColumns(10);

        JLabel lblFirstNumber = new JLabel("First Number");
        lblFirstNumber.setBounds(6, 128, 87, 16);
        getContentPane().add(lblFirstNumber);

        JLabel lblSecondNumber = new JLabel("Second Number");
        lblSecondNumber.setBounds(6, 156, 105, 16);
        getContentPane().add(lblSecondNumber);

        txtSecondNumber = new JTextField();
        txtSecondNumber.setBounds(109, 151, 97, 26);
        getContentPane().add(txtSecondNumber);
        txtSecondNumber.setColumns(10);

        lblError = new JLabel("");
        lblError.setVerticalAlignment(SwingConstants.BOTTOM);
        lblError.setHorizontalAlignment(SwingConstants.CENTER);
        lblError.setBounds(6, 190, 189, 126);
        getContentPane().add(lblError);
    }
    int Final = 0;
    private JTextField txtFirstNumber;
    private JTextField txtSecondNumber;

    public int doMath(int number1, String opreator, int number2) {
        try {
            switch (opreator) {
            case "+":
                Final = number1 + number2;
                lblError.setText("");
                break;
            case "-":
                Final = number1 - number2;
                lblError.setText("");
                break;
            case "*":
                Final = number1 * number2;
                lblError.setText("");
                break;
            case "/":
                Final = number1 / number2;
                lblError.setText("");
                break;
            case "%":
                Final = number1 % number2;
                lblError.setText("");
                break;
            default:
                lblError.setText("Error: had to do with opreator");
            }
        } catch (Exception e) {
            lblError.setText("Please use small numbers");
        }
        return Final;
    }

    public static void main(String[] args) {
        MathGUI math = new MathGUI();
        math.setSize(new Dimension(331,351));
        math.setVisible(true);


    }
}