Why is the program not running? Is there a logical or syntax problem?

[deanhystad]

Use the Python button in the editor to wrap your code in Python tags.

You still have an error in root().

And you have a new indentation error:

        self.res_label.config(text=result)
        # create the main window and profit object
        # create the main window and profit object
        root = tk.Tk()
        pro = Profit(root)
        root.mainloop()

As currently written, you are making root inside the calculate() method.

And this indentation is also wrong, though it probably doesn't stop your code running.

    def rule(master):
          return 72/master

The rest of your code uses 4 space indents. This has 8 spaces. Be consistent.