text: from tkinter import *
  
  # Init the app
  root = Tk()
  root.title("Simple Calculator")
  
  # Init text entry
  entry = Entry(root, width=40, borderwidth=5)
  entry.grid(row=0, column=0, columnspan=3, padx=10, pady=10)
  
  # Init global variables
  first_num = None
  math = None
  
  # Define button actions
  def button_click(number):
      entry.insert(END, number)
  
  def button_clear():
      entry.delete(0, END)
  
  def button_add():
      first_number = entry.get()
      global first_num
      global math
      math = "addition"
      first_num = int(first_number)
      entry.delete(0, END)
  
  def button_subtract():
      first_number = entry.get()
      global first_num
      global math
      math = "subtraction"
      first_num = int(first_number)
      entry.delete(0, END)
  
  def button_multiply():
      first_number = entry.get()
      global first_num
      global math
      math = "multiplication"
      first_num = int(first_number)
      entry.delete(0, END)
  
  def button_divide():
      first_number = entry.get()
      global first_num
      global math
      math = "division"
      first_num = int(first_number)
      entry.delete(0, END)
  
  def button_equal():
      second_number = entry.get()
      entry.delete(0, END)
  
      if math == "addition":
          entry.insert(0, first_num + int(second_number))
  
      if math == "subtraction":
          entry.insert(0, first_num - int(second_number))
  
      if math == "multiplication":
          entry.insert(0, first_num * int(second_number))
  
      if math == "division":
          entry.insert(0, first_num / int(second_number))
  
  # Define buttons
  button_0 = Button(root, text="0", padx=135, pady=20, command=lambda:button_click(0))
  button_1 = Button(root, text="1", padx=40, pady=20, command=lambda:button_click(1))
  button_2 = Button(root, text="2", padx=40, pady=20, command=lambda:button_click(2))
  button_3 = Button(root, text="3", padx=40, pady=20, command=lambda:button_click(3))
  button_4 = Button(root, text="4", padx=40, pady=20, command=lambda:button_click(4))
  button_5 = Button(root, text="5", padx=40, pady=20, command=lambda:button_click(5))
  button_6 = Button(root, text="6", padx=40, pady=20, command=lambda:button_click(6))
  button_7 = Button(root, text="7", padx=40, pady=20, command=lambda:button_click(7))
  button_8 = Button(root, text="8", padx=40, pady=20, command=lambda:button_click(8))
  button_9 = Button(root, text="9", padx=40, pady=20, command=lambda:button_click(9))
  
  button_add = Button(root, text="+", padx=40, pady=20, command=button_add)
  button_subtract = Button(root, text="-", padx=41, pady=20, command=button_subtract)
  button_multiply = Button(root, text="x", padx=40, pady=20, command=button_multiply)
  button_divide = Button(root, text="/", padx=41, pady=20, command=button_divide)
  button_equal = Button(root, text="=", padx=87, pady=20, command=button_equal)
  button_clear = Button(root, text="Clear", padx=77, pady=20, command=button_clear)
  
  
  # Put buttons on the screen
  button_0.grid(row=4, column=0, columnspan=3)
  button_1.grid(row=3, column=0)
  button_2.grid(row=3, column=1)
  button_3.grid(row=3, column=2)
  
  button_4.grid(row=2, column=0)
  button_5.grid(row=2, column=1)
  button_6.grid(row=2, column=2)
  
  button_7.grid(row=1, column=0)
  button_8.grid(row=1, column=1)
  button_9.grid(row=1, column=2)
  
  button_clear.grid(row=5, column=0, columnspan=2)
  button_equal.grid(row=5, column=2, columnspan=2)
  
  button_add.grid(row=4, column=3)
  button_subtract.grid(row=3, column=3)
  button_multiply.grid(row=2, column=3)
  button_divide.grid(row=1, column=3)
  
  # Keep the app running
  root.mainloop()
  