title: How to bring up symbols in Python ttk.buttons
body: <p>I am learning Python3x tkinter on self-study. Practising geometry management widgets, I have designed a calculator that looks somehow like MS Windows Basic Claculator, a snapshot is provided below. The buttons were created with ttk.Button module.  As you see, I could not add the text on backspace arrow &lt;--, +/- and sqrt buttons as exactly they look on MS Windows Calculator. How can I do that? I hope there is a way to add symbols to buttons. I think using bitmap images is not a good option because there will be no harmony amongst the buttons:i.e. buttons with bitmap images will look different than those with text. </p>
  
  <p>Here is a part of the code which needs to be modified to show the symbols correctly:</p>
  
  <pre><code>from tkinter import *
  from tkinter import ttk
  root = Tk()
  backspace = ttk.Button(root, text="&lt;--") 
  backspace.grid(row=0, column=0, padx=2, pady=0, sticky="nw")
  
  plusminus = ttk.Button(root, text="+/-")
  plusminus.grid(row=0, column=1, padx=2, pady=2, sticky="nw")
  
  sqroot = ttk.Button(root, text="sqrt")
  sqroot.grid(row=0, column=2, padx=2, pady=2, sticky="nw")
  
  root.mainloop()
  </code></pre>
  
  <p>Your help is highly appreciated!</p>
  
  <p><img src="https://i.stack.imgur.com/s10BC.jpg" alt="Snapshot of my calculator"> </p>