from tkinter import *
def OTVET():
    x = int(first_entry.get())
    y = int(second_entry.get())
    ansLabel.config(text ="Ответ: " + str(x+y))
    buttonAns.configure(state = DISABLED)
def Fclear():
    first_entry.delete(0,'end')
    second_entry.delete(0,'end')
    ansLabel.config(text ="Ответ: ")
    first_entry.focus()
root = Tk()
root.title("Сумма чисел")

first = IntVar()
second = IntVar()

first_label = Label(text="Первое число: ")
second_label = Label(text="Второе число: ")
ansLabel = Label(text ="Ответ: ")
first_label.grid(row=0, column=0, sticky="w")
second_label.grid(row=1, column=0, sticky="w")
ansLabel.grid(row=2,column=0,sticky = "w")
first_entry = Entry(textvariable=first)
second_entry = Entry(textvariable=second)

first_entry.grid(row=0, column=1, padx=5, pady=5)
second_entry.grid(row=1, column=1, padx=5, pady=5)

buttonAns = Button(text="Вычислить", command=OTVET)
buttonAns.grid(row=2, column=1, padx=5, pady=5, sticky="e")
btnClear = Button (text="Очистить",command =  Fclear)
btnClear.grid(row = 3, column = 1, padx = 5,pady = 5,sticky ="e")
root.mainloop()