123

from tkinter import *

def calculator():
    res = '{}'. format(txt.get())
    res = int(res)
    lbl.configure(text=res)


window = Tk()
window.title('calculator')
window.geometry('400x250')
btn = Button(window, text = '~~~', command=calculator)
btn.grid(column=6, row=0)
lbl = Label(window, text='0')
lbl.grid(column=8, row=0)
txt = Entry(window,width=10)
txt.grid(column=4, row = 0)
window.mainloop()