Calculator with Tkinter

Hello, I have written a program in which, among other things, a calculator is installed. However, there should actually be a 0 in the text fields and a + in the option menus. Thanks in advance!
Here is the program:

from tkinter import *
import tkinter.ttk as ttk
    var1_ = IntVar()
    var2_ = IntVar()
    var3_ = IntVar()
    var4_ = IntVar()
    var5_ = IntVar()
    entry1 = Entry(master=root, textvariable=var1_, font="Segoe 20"), y=100, width=600, height=40)
    entry2 = Entry(master=root, textvariable=var2_, font="Segoe 20"), y=200, width=600, height=40)
    entry3 = Entry(master=root, textvariable=var3_, font="Segoe 20"), y=300, width=600, height=40)
    entry4 = Entry(master=root, textvariable=var4_, font="Segoe 20"), y=400, width=600, height=40)
    entry5 = Entry(master=root, textvariable=var5_, font="Segoe 20"), y=500, width=600, height=40)
    variable = StringVar()
    dropdown1 = OptionMenu(root, variable, *__x__)
    dropdown1.pack(expand=True), y=150, width=600, height=40)
    variable1 = StringVar()
    dropdown2 = OptionMenu(root, variable1, *__z__)
    dropdown2.pack(expand=True), y=250, width=600, height=40)
    variable2 = StringVar()
    dropdown3 = OptionMenu(root, variable2, *__b__)
    dropdown3.pack(expand=True), y=350, width=600, height=40)
    variable3 = StringVar()
    dropdown4 = OptionMenu(root, variable3, *__n__)
    dropdown4.pack(expand=True), y=450, width=600, height=40)

When asking for help, one should write the minimal code needed to illustrate the issue. 1 to 20 usually suffices. Expecting people to read hundreds of lines pick out the few relevant lines is unrealistic. Without reading, I don’t know what you mean by “0 in the text fields and a + in the option menus”