tkinter calc

from tkinter import *

w = Tk()
w.title("Operator")

e1 = Entry(w, bd = 3, font = "helvetica")
e2 = Entry(w, bd = 3, font = "helvetica")
operator_e = Entry(w, bd = 3, font = "helvetica")

e1.grid(row = 0, column = 0)
e2.grid(row = 0, column = 2)
operator_e.grid(row = 0, column = 1)

def callback():
    if operator_e.get() == "+":
        answer_label1 = Label(w, text = int(e1.get()) + int(e2.get()))
        answer_label1.grid(row = 3, column = 1)
    elif operator_e.get() == "-":
        answer_label2 = Label(w, text = int(e1.get()) - int(e2.get()))
        answer_label2.grid(row = 3, column = 1)
    elif operator_e.get() == "*":
        answer_label3 = Label(text = int(e1.get()) * int(e2.get()))
        answer_label3.grid(row = 3, column = 1)
    else:
        pass

b_exec = Button(w, text = "click", command = callback, bd = 5, font = "helvetica")
b_exec.grid(row = 2, column = 1)

w.mainloop()