Independent practice calling functions

Hi, I am currently working on Independent practice to work on the skills I have learned with python. note that the code is purposefully not “beautiful code” in an attempt to practice specific tools and structures within python. currently I am having the issue of calling functions and passing variables between functions or (returning variables). Note that there are commented out segments and the looping structure is still a work in progress. I would like to not only solve this issue but possibly even make this an exercise in the python modules. The code I have is as follows:
#skill keeper tests
#basic Calc app
#long way
#author: JV
#Pseudo code: create basic calculator app
#main menu must give value input options for subtraction
#addition, multiplication and division
#for sake of time will only work with two value inputs
#will not use read write or log functions to create history logs of value outputs
#will be looping structure for main screen use
#calculator will not make use of floats
#main code as follows:

#global choice_selected
def main_menu():
#while choice_selected != str((“A”,“B”,“C”,“D”)):
print(“Calculator app”)
print(“Note this app ONLY functions with whole numbers! \n”)
print(“Main Menu:\n”)
print(“This is a basic calculator app\n”.center(50))
print(“A) Addition \n”)
print(“B) Subtraction \n”)
print(“C) Multiplication \n”)
print(“D) Division \n”)
global choice_selected
choice_selected=(input("please make your operator selection by choosing from the menu: ").upper())
def option_selected(choice_selected):
if choice_selected==A:
elif choice_selected==B:
elif choice_selected==C:
elif choice_selected==D:
print(“Error Value entered not recognized in system, please make a selection from the given values.”)
def addition_operator():
print(“Addition Selected.”)
Value_1=(int(input(“enter first integer for the addition problem.”)))
Value_2=(int(input(“enter second integer to be added.”)))
print("the sum of these two integers is: ",Value_1+Value_2)
def subtraction_operator():
print(“Subtraction selected.”)
Value_1=(int(input(“Enter the first integer to be Subtracted.”)))
Value_2=(int(input(“Enter the second integer that will subtract.”)))
print("The Difference between these two numbers is: ",Value_1-Value_2)
def multiplication_operator():
print(“Multiplication selected.”)
Value_1=(int(input(“Enter the first integer to be multiplied.”)))
Value_2=(int(input(“Enter the integer to be multiplied by.”)))
print("The Product of these two numbers is: ",Value_1*Value_2)
def division_operator():
print(“Devision selected.”)
Value_1=(int(input(“Enter the integer to be Devided.”)))
Value_2=(int(input(“Enter the ammount to Devide by.”)))
print("The quotient of these two numbers is: ",Value_1%Value_2)


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