from tkinter import *


def km2miles():
    miles = float(e1_value.get()) * 1.6
    t1.insert(END, miles)


window = Tk()
b1 = Button(window, text="Execute", command=km2miles)
b1.grid(row=0, column=0)
e1_value = StringVar()
e1 = Entry(window, textvariable=e1_value)
e1.grid(row=0, column=1)
t1 = Text(window, height=1, width=20)
t1.grid(row=0, column=2)
window.mainloop()
