from tkinter import *

window = Tk()
window.title("My Calculator")
display = Entry(window, width=33, bg="yellow")
display.grid(row=0,column=0,columnspan=5)

button_list=[
'7','8','9','/','C',
'4','5','6','*',' ',
'1','2','3','-',' ',
'0','.','=','+',' ' ]

def click(key):
    if key == "=":
        result= eval(display.get())
        s= str(result)
        display.insert(END,"=" +s)
    else:
        display.insert(END,key)

row_index =1
col_index =0
for button_text in button_list:
    def process(t=button_text):
        click(t)
    Button(window,text=button_text,width=5,command=process).grid(row=row_index, column=col_index)
    col_index += 1
    if col_index >4:
        row_index +=1
        col_index=0

window.mainloop()