text: 
  from tkinter import * #This imports everything :: importing the libraries
  expression=" "             #globally declared the expression variable
  #function to update the expression in the text entry box
  def press(num):
      global expression #point out the global expression variable
      expression=expression+str(num)#concatenation of string
      equation.set(expression) #update the expression by using set method
      
      #Function to evaluate the final expression
  def equalpress():
          #Try and except block statement for handling errors wrt to zero division error etc
          try:
              global expression
              #Eval function evaluatuont he expression and str function converts the result into string
              total =str(eval(expression))
              equation.set(total)
              #initialise the expression variable by empty string
              expression = ""
              #if error is generated then handle by the except block
          except:
              equation.set("Error")
              expression=""
      
   #Function to clear the contents of text entry box
  def clear():
      global expression
      expression=""
      equation.set("")
  
  
  #DriverCode
  
  #Create a GUI WIndow
  gui=Tk()
  
  #Set Window Background
  gui.configure(background="black")
  #set configuration of Window
  gui.geometry('270x150')
  #Set GUI Title
  gui.title("Simple Calculator")
  #Creating Expression field
  equation=StringVar()
  expression_field=Entry(gui,textvariable=equation)
  expression_field.grid(columnspan=4,ipadx=70)
  #Creating Buttons
  button1=Button(gui,text='1',fg='white',bg='black',command=lambda:press(1),height=1,width=5)
  button1.grid(row=2,column=0)
  button2=Button(gui,text='2',fg='white',bg='black',command=lambda:press(2),height=1,width=5)
  button2.grid(row=2,column=1)
  button3=Button(gui,text='3',fg='white',bg='black',command=lambda:press(3),height=1,width=5)
  button3.grid(row=2,column=2)
  button4=Button(gui,text='4',fg='white',bg='black',command=lambda:press(4),height=1,width=5)
  button4.grid(row=3,column=0)
  button5=Button(gui,text='5',fg='white',bg='black',command=lambda:press(5),height=1,width=5)
  button5.grid(row=3,column=1)
  button6=Button(gui,text='6',fg='white',bg='black',command=lambda:press(6),height=1,width=5)
  button6.grid(row=3,column=2)
  button7=Button(gui,text='7',fg='white',bg='black',command=lambda:press(7),height=1,width=5)
  button7.grid(row=4,column=0)
  button8=Button(gui,text='8',fg='white',bg='black',command=lambda:press(8),height=1,width=5)
  button8.grid(row=4,column=1)
  button9=Button(gui,text='9',fg='white',bg='black',command=lambda:press(9),height=1,width=5)
  button9.grid(row=4,column=2)
  button10=Button(gui,text='0',fg='white',bg='black',command=lambda:press(0),height=1,width=5)
  button10.grid(row=5,column=0)
  plus=Button(gui,text='+',fg='white',bg='black',command=lambda:press('+'),height=1,width=5)
  plus.grid(row=2,column=3)
  multiply=Button(gui,text='*',fg='white',bg='black',command=lambda:press('*'),height=1,width=5)
  multiply.grid(row=3,column=3)
  divide=Button(gui,text='/',fg='white',bg='black',command=lambda:press('/'),height=1,width=5)
  divide.grid(row=4,column=3)
  minus=Button(gui,text='-',fg='white',bg='black',command=lambda:press('-'),height=1,width=5)
  minus.grid(row=5,column=1)
  decimal=Button(gui,text='.',fg='white',bg='black',command=lambda:press('.'),height=1,width=5)
  decimal.grid(row=5,column=2)
  equal=Button(gui,text='=',fg='white',bg='black',command=equalpress,height=1,width=5)
  equal.grid(row=5,column=3)
  clear=Button(gui,text='clear',fg='white',bg='black',command=clear,height=1,width=5)
  clear.grid(row=6,column=0)
  
  
  
  #main Loop
  gui.mainloop()
  
  