laskin.py

from tkinter import *
from tkinter import messagebox

import sys
expression = ""

def press(num):
    global expression
    expression = expression + str(num)
    equation.set(expression)


def equalpress():
    try:
        global expression
        total = str(eval(expression))
        equation.set(total)
        expression = ""

    except:
        equation.set(" error ")
        expression = ""

def clear():
    global expression
    expression = ""
    equation.set("")

def quit():
    global expression
    gui.destroy()

if __name__ == "__main__":
    gui = Tk()
    gui.title("Calculator")
    gui.geometry("200x250")

    ###FIX THIS######FIX THIS######FIX THIS######FIX THIS###
    backgroundImage = PhotoImage("C:\\Users\\erik\\Pictures\\bg.gif")

equation = StringVar()

expression_field = Entry(gui, textvariable=equation)
expression_field.grid(columnspan=4, ipadx=70)

equation.set('. . .')

B1 = Button(gui, text=' 1 ', fg='Black', bg='White',
                    command=lambda: press(1), height=1, width=7)
B1.grid(row=2, column=0)

B2 = Button(gui, text=' 2 ', fg='Black', bg='White',
                    command=lambda: press(2), height=1, width=7)
B2.grid(row=2, column=1)

B3 = Button(gui, text=' 3 ', fg='Black', bg='White',
                    command=lambda: press(3), height=1, width=7)
B3.grid(row=2, column=2)

B4 = Button(gui, text=' 4 ', fg='Black', bg='White',
                    command=lambda: press(4), height=1, width=7)
B4.grid(row=3, column=0)

B5 = Button(gui, text=' 5 ', fg='Black', bg='White',
                    command=lambda: press(5), height=1, width=7)
B5.grid(row=3, column=1)

B6 = Button(gui, text=' 6 ', fg='Black', bg='White',
                    command=lambda: press(6), height=1, width=7)
B6.grid(row=3, column=2)

B7 = Button(gui, text=' 7 ', fg='Black', bg='White',
                    command=lambda: press(7), height=1, width=7)
B7.grid(row=4, column=0)

B8 = Button(gui, text=' 8 ', fg='Black', bg='White',
                    command=lambda: press(8), height=1, width=7)
B8.grid(row=4, column=1)

B9 = Button(gui, text=' 9 ', fg='Black', bg='White',
                    command=lambda: press(9), height=1, width=7)
B9.grid(row=4, column=2)

B0 = Button(gui, text=' 0 ', fg='Black', bg='White',
                    command=lambda: press(0), height=1, width=7)
B0.grid(row=5, column=0)

plus = Button(gui, text=' + ', fg='Black', bg='White',
                command=lambda: press("+"), height=1, width=7)
plus.grid(row=2, column=3)

minus = Button(gui, text=' - ', fg='Black', bg='White',
                command=lambda: press("-"), height=1, width=7)
minus.grid(row=3, column=3)

multiply = Button(gui, text=' * ', fg='Black', bg='White',
                    command=lambda: press("*"), height=1, width=7)
multiply.grid(row=4, column=3)

divide = Button(gui, text=' / ', fg='Black', bg='White',
                    command=lambda: press("/"), height=1, width=7)
divide.grid(row=5, column=3)

equal = Button(gui, text=' = ', fg='Black', bg='White',
                command=equalpress, height=1, width=7)
equal.grid(row=5, column=2)

clear = Button(gui, text='Clear', fg='Black', bg='White',
                command=clear, height=1, width=7)
clear.grid(row=5, column=1)

close = Button(gui, text= 'Quit', fg='Black', bg='White',
                command=quit, height=1, width=7)
close.grid(row=7, column=1)
    # start the GUI

gui.mainloop()