Remove Widget from Tkinter in function

Question

I want to remove the result from lable_result after it packed in root window GUI_calculate. and here is my code:

def GUI_calculate():
    num =  number.get()
    fact = calculate_factorial(int(num))
    lable_result = Label(text=f'Factorial : {num} = {str(fact)}')
    lable_result.pack()
root = Tk()
root.geometry('200x200')
root.title('calculate factorial')
# root.configure(background='lightgray')
lable = Label(text='enter number ',font=("Arial", 25))
lable.pack()
number = Entry(width=5)
number.pack()
btn = Button(command=GUI_calculate,text='calc')
btn.pack()
root.mainloop()