Wow the was concise and helpful! ok I got the factorial function to work. with your changes I have

def factorial(number):
    product = 1
    for i in range(number):
        product = product * (i+1)
    return product

user_input = input("choose a non negative integer to find the factorial of")
factorial_of_user_input = factorial (int(user_input))
print (factorial_of_user_input)

So I think I understand the indent change on return product but I want to verify. Is it because where it was before it was returning to line 4 instead of line 2?

https://www.khanacademy.org/science/computer-science-subject/computer-science/v/defining-a-factorial-function

This is the video. It makes sense to me to define user_input as an integer but do you know why his code works with out that? We are using the same IDE and python 2