GUI2.py

from tkinter import *
window = Tk()
window.title("Assignment 2")
lbl1 = Label(window, text="Enter First Number: ")
lbl1.grid(column=1, row=1)
txt1 = Entry(window,width=10)
txt1.grid(column=2, row=1)
lbl2 = Label(window, text="Enter Second Number: ")
lbl2.grid(column=1, row=2)
txt2 = Entry(window,width=10)
txt2.grid(column=2, row=2)
lbl3 = Label(window, text="Result: ")
lbl3.grid(column=1, row=3)
txt3 = Entry(window,width=10)
txt3.grid(column=2, row=3)
def addF():
    a = float(txt1.get())
    b = float(txt2.get())
    sum = a + b
    txt3.delete(0, END)
    txt3.insert(END, sum)
def subF():
    a = float(txt1.get())
    b = float(txt2.get())
    sub = a - b
    txt3.delete(0, END)
    txt3.insert(END, sub)
add = Button(window, text="Add", command=addF)
add.grid(column=1, row=4)
add = Button(window, text="Subtract", command=subF)
add.grid(column=2, row=4)
window.mainloop()