Hello

import tkinter as tk
class Application (tk.Frame):
    def __init__(self, master=None):
        super () .__init__(master)

        self.pack ()

    app = Application ()
    app.master.title("Sumator")
    app.master.minsize (width=100, height=50)
    app.mainloop()

    def __init__(self, master=None):
        super() .__init__(master)

        self.pack()
        self.create_widgets()

        def create_widgets(self):
            self.firstNumberEntry = tk.Entry()
            self.plusSign = tk.Label(text="+")
            self.secondNumberEntry = tk.Entry()
            self.equalSign = tk.Label(text="=")
            self.resultLAbel = tk.Label(text="Result...", bg="green", fg="white")
            self.calculateButton = tk.Button(text="Calculate")

            self.firstNumberEntry.pack(side="left")
            self.plusSign.pack(side="left")
            self.secondNumberEntry.pack(side="left")
            self.equalSign.pack(side="left")
            self.resultLabel.pack(side="left")
            self.calculateButton.pack(side="left")