Simple calculator using python and tkinter

 from re import sub

from tkinter import *

#creating a window

root =  Tk()

#decale the default variable

calc = ""

#definig the function

def addi():

    global calc

    calc += "+"

    pop['text'] = calc

def subi():

    global calc

    calc += "-"

    pop['text'] = calc

def divi():

    global calc

    calc += "/"

    pop['text'] = calc

def multipl():

    global calc

    calc += "*"

    pop['text'] = calc

def ze():

    global calc

    calc += "0"

    pop['text'] = calc

def on():

    global calc

    calc += "1"

    pop['text'] = calc

def tw():

    global calc

    calc += "2"

    pop['text'] = calc

def th():

    global calc

    calc += "3"

    pop['text'] = calc

def fo():

    global calc

    calc += "4"

    pop['text'] = calc

def fi():

    global calc

    calc += "5"

    pop['text'] = calc

def si():

    global calc

    calc += "6"

    pop['text'] = calc

def se():

    global calc

    calc += "7"

    pop['text'] = calc

def ei():

    global calc

    calc += "8"

    pop['text'] = calc

def ni():

    global calc

    calc += "9"

    pop['text'] = calc

def decii():

    global calc

    calc += "."

    pop["text"] = calc

def evali():

    global calc

    try:

        calc = eval(calc)

        pop["text"] = calc

        calc = ""

    except:

        pop['text'] = "AN ERROR OCCURRED"

        calc = ""

def cleari():

    global calc

    calc = ""

    pop["text"] = calc

#naming the window

root.title("A SIMPLE CALCULATOR")

#label and entry field

m = Label(root, text="CALCULATOR", font=(25))

pop = Label(root, text='', font=(50))

#operators box

adding = Button(root, text="+",height=2, width=5, command=addi)

subtracting = Button(root, text="-",height=2, width=5, command=subi)

dividing = Button(root, text="/",height=2, width=5, command=divi)

multiplying = Button(root, text="*",height=2, width=5, command=multipl)

equating = Button(root, text="=", height=10, width=13, command=evali)

#numbers

nine = Button(root, text="9", height=2, width=5, command=ni)

eight = Button(root, text="8", height=2, width=5, command=ei)

seven = Button(root, text="7", height=2, width=5, command=se)

six = Button(root, text="6", height=2, width=5, command=si)

five = Button(root, text="5", height=2, width=5, command=fi)

four = Button(root, text="4", height=2, width=5, command=fo)

three = Button(root, text="3", height=2, width=5, command=th)

two = Button(root, text="2", height=2, width=5, command=tw)

one = Button(root, text="1", height=2, width=5, command=on)

zero = Button(root, text="0", height=2, width=5, command=ze)

ccc = Button(root, text="C", height=2, width=5, command=cleari)

deci = Button(root, text=".", height=2, width=5, command=decii)

#placing on screen

m.place(x=190, y=0)

pop.place(x=100, y=30)

#placiing operators

adding.place(x=100, y=60)

subtracting.place(x=150, y=60)

dividing.place(x=200, y=60)

multiplying.place(x=250, y=60)

equating.place(x=300, y=60)

#placing digits

nine.place(x=100, y=100)

eight.place(x=150, y=100)

seven.place(x=200, y=100)

six.place(x=250, y=100)

five.place(x=100, y=140)

four.place(x=150, y=140)

three.place(x=200, y=140)

two.place(x=250, y=140)

ccc.place(x=100, y=180)

one.place(x=150, y=180)

zero.place(x=200, y=180)

deci.place(x=250, y=180)

root.resizable(False, False)

root.geometry("500x500")

root.mainloop()

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