Student Marks Calculation using Java FX

package controller;

import javafx.event.ActionEvent;
import javafx.scene.control.TextField;
import javafx.scene.layout.AnchorPane;

public class StudentMarksFormController
{
    
    public TextField txtMarks1;
    public TextField txtMarks2;
    public TextField txtMarks3;
    public TextField txtTot;
    public TextField txtAvg;
    public TextField txtGrade;

    public AnchorPane pane;

    public void BtnCalculate(ActionEvent actionEvent) {

        int mark1 = Integer.parseInt(txtMarks1.getText());
        int mark2 = Integer.parseInt(txtMarks2.getText());
        int mark3 = Integer.parseInt(txtMarks3.getText());

        int tot = mark1 + mark2 +  mark3;

        txtTot.setText(String.valueOf(tot));

        double avg = tot/3;

        txtAvg.setText(String.valueOf(avg));

        String Grade;
        if(avg > 50)
        {
            Grade = "Pass";
        }
        else
        {
            Grade = "Fail";
        }


        txtGrade.setText(Grade);

    }

    public void BtnClear(ActionEvent actionEvent) {

        txtMarks1.setText("");
        txtMarks2.setText("");
        txtMarks3.setText("");
        txtTot.setText("");
        txtAvg.setText("");
        txtGrade.setText("");
        txtMarks1.requestFocus();


    }
}

i have attached the video link below. which will do this tutorials step by step.