Java GUI找不到添加的方法？

对于一个基本的课堂作业，我们只需要做一个基本计算器的GUI，但是有3个错误一直困扰着我，我一辈子都无法解决

    C:\Users\Novus\Desktop\STC Notes\OO Scripts\CalcGUI.java:62: error: no suitablemethod found for add(String,GridLayout)
        Mathpane.add("Center", Numgrid);
                ^
method Container.add(String,Component) is not applicable
  (argument mismatch; GridLayout cannot be converted to Component)
method Container.add(Component,int) is not applicable
  (argument mismatch; String cannot be converted to Component)
method Container.add(Component,Object) is not applicable
  (argument mismatch; String cannot be converted to Component)

 C:\Users\Novus\Desktop\STC Notes\OO Scripts\CalcGUI.java:63: error: no suitable method found for add(String,GridLayout)
        Mathpane.add ("East", Signsgrid);
                ^
method Container.add(String,Component) is not applicable
  (argument mismatch; GridLayout cannot be converted to Component)
method Container.add(Component,int) is not applicable
  (argument mismatch; String cannot be converted to Component)
method Container.add(Component,Object) is not applicable
  (argument mismatch; String cannot be converted to Component)

 C:\Users\Novus\Desktop\STC Notes\OO Scripts\CalcGUI.java:72: error: no suitable method found for add(String,BorderLayout)
        Finalpane.add("Center", MathBorder);
                 ^
method Container.add(String,Component) is not applicable
  (argument mismatch; BorderLayout cannot be converted to Component)
method Container.add(Component,int) is not applicable
  (argument mismatch; String cannot be converted to Component)
method Container.add(Component,Object) is not applicable
  (argument mismatch; String cannot be converted to Component)
    Note: Some messages have been simplified; recompile with -Xdiags:verbose  to get full output

这些是错误，下面是代码

import javax.swing.*;
import java.awt.*;

class Calculator
    {
         public static void main (String args[])
        {
            JFrame = new CalcGUI();
            Jframe.setSize(420,720);
            JFrame.setVisible(true);
        }
    }

第二部分

import javax.swing.*;
import java.awt.*;

 public class CalcGUI extends JFrame
 {
 BorderLayout FinalBorder = new BorderLayout();
 GridLayout Numgrid = new GridLayout(4,3,15,15);
 GridLayout Signsgrid = new GridLayout(5,1,7,7);
 BorderLayout MathBorder = new BorderLayout();
JPanel Finalpane = new JPanel();
JPanel Mathpane = new JPanel();
JPanel Signpane = new JPanel();
JPanel Numpane = new JPanel();
JLabel Casio = new JLabel("Casio", JLabel.CENTER);
JTextField txt_InputNum = new JTextField();
JButton Btn7 = new JButton("7");
JButton Btn8 = new JButton("8");
JButton Btn9 = new JButton("9");
JButton Btn4 = new JButton("4");
JButton Btn5 = new JButton("5");
JButton Btn6 = new JButton("6");
JButton Btn1 = new JButton("1");
JButton Btn2 = new JButton("2");
JButton Btn3 = new JButton("3");
JButton Btn_deci = new JButton(".");
JButton Btn0 = new JButton("0");
JButton Btn_clear = new JButton("C");
JButton Btn_mult = new JButton("*");
JButton Btn_div = new JButton("/");
JButton Btn_add = new JButton("+");
JButton Btn_minus = new JButton("-");
JButton Btn_equals = new JButton("=");


    public CalcGUI ()
    {
       super ("Calculator");

        Numpane.setLayout(Numgrid);
        Numpane.add(Btn7);
        Numpane.add(Btn8);
        Numpane.add(Btn9);
        Numpane.add(Btn4);
        Numpane.add(Btn5);
        Numpane.add(Btn6);
        Numpane.add(Btn1);
        Numpane.add(Btn2);
        Numpane.add(Btn3);
        Numpane.add(Btn_deci);
        Numpane.add(Btn0);
        Numpane.add(Btn_clear);

        Signpane.setLayout(Signsgrid);
        Signpane.add(Btn_mult);
        Signpane.add(Btn_div);
        Signpane.add(Btn_add);
        Signpane.add(Btn_minus);
        Signpane.add(Btn_equals);


        Mathpane.setLayout(MathBorder);
        Mathpane.add("Center", Numgrid);
        Mathpane.add ("East", Signsgrid);



        //super ("Calculator");
        //setDefaultCloseOperation(JFrame (EXIT_ON_CLOSE));

        Finalpane.setLayout(FinalBorder);
        Finalpane.add("North", txt_InputNum);
        Finalpane.add("Center", MathBorder);
        Finalpane.add("South", Casio);

     setContentPane(Finalpane);

}
  }

---

我还处于java的基础阶段，所以请让提示或答案对我来说很简单，谢谢

字符串不是组件：请尝试使用标签或JLabelJFrame作为类名，您需要创建JFrame类型的对象，例如“JFrame myFrame=new JFrame（）”，然后与“myFrame”交互