n1 = int(input("enter number: "))
n2 = int(input("enter number: "))

user_input = input("what would you like to do, 1) add, 2) minus, 3) multiply, 4) divide, 5) all: ")

def my_function_add(a, b):
   print(a + b)

def my_function_minus(a, b):
    print(a - b)

def my_function_multiply(a, b):
    print(a * b)

def my_function_divide(a, b):
    print(a / b)

def my_function_all(a, b):
    my_function_add(a, b)
    my_function_minus(a, b)
    my_function_multiply(a, b)
    my_function_divide(a, b)

my_dict = {'add': my_function_add,
           'minus' : my_function_minus,
           'multiply' : my_function_multiply,
           'divide' : my_function_divide,
           'all': my_function_all,
          }

def my_selection(name):
    my_dict.get(name)(n1, n2)

if user_input == '1' or user_input == 'add':
    my_selection('add')

elif user_input == '2' or user_input == 'minus':
    my_selection('minus')

elif user_input == '3' or user_input == 'multiply':
    my_selection('multiply')

elif user_input == '4' or user_input == 'divide':
    my_selection('divide')

elif user_input == '5' or user_input == 'all':
    my_selection('all')

else:
    print("I do not understand, pick a number or write the calculation you want")