from tkinter import *
root = Tk()
root.title("simple calculator")
e =Entry(root, width=50,borderwidth=3)
e.grid(row=0,column=0,columnspan=3,padx=10,pady=10)





def button_click(number):
	current =e.get()
	e.delete(0,END)
	e.insert(0,str(current) + str(number))

def button_add():
	first_number = e.get()
	global f_num
	f_num = int(first_number)
	e.delete(0,END)


def button_equal():
	second_number = e.get()
	e.delete(0,END)
	e.insert(0,f_num + int(second_number))

def button_clear():
	e.delete(0,END)

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_0 = Button(root, text="0", padx=40, pady=20,command=lambda:button_click(0))
button_add = Button(root, text="+", padx=39, pady=20,command=button_add)
button_equal = Button(root, text="=", padx=91, pady=20,command=button_equal)
button_clear = Button(root, text="Clear", padx=83, pady=20,command=button_clear)


#put buttons on  the screen

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_0.grid(row=4, column=0)
button_clear.grid(row=4, column=1,columnspan=2)
button_add.grid(row=5, column=0)
button_equal.grid(row=5, column=1,columnspan=2)



root.mainloop()