Калькулятор с интерфейсом

from tkinter import *
 
 
def clicked():
    x,y,z=map(int,str(entry.get()).split())
 
 
def count(original_number,number_of_oper,multiplier):
    if number_of_oper==1:
        return(original_number+multiplier)
    elif number_of_oper==2:
        return(original_number*multiplier)
    elif number_of_oper==3:
        return(original_number**multiplier)
    elif number_of_oper==4:
        return(tetr(original_number,multiplier))
    elif number_of_oper==5:
        return(pent(original_number,multiplier))
 
 
def tetr(original_number,exponent_of_tetr):
    res=original_number
    for i in range(exponent_of_tetr-1):
        res=original_number**res
    return res
 
def pent(original_number,exponent_of_pent):
    res=original_number
    for i in range(exponent_of_pent-1):
        res=tetr(original_number,res)
    return res
 
 
res=0
root=Tk()
root.title('Калькулятор')
root.geometry('200x75')
root.iconbitmap(r'C:\Users\Pc\Desktop\Новый точечный рисунок.ico')
entry=Entry(root,
            width=10,
            font=("Arial Bold", 20),
            justify=CENTER)
entry.grid(column=0, row=0)
btn = Button(text="Enter",
             command=clicked)
btn.grid(column=1, row=0)
txt=Label(root,
          text=res,
          font=("Arial Bold", 25))
txt.grid(column=0, row=1)
 
 
root.mainloop()
txt=count(x,y,z)