How to make authorization on the site using a question?

Question

User identification

I am making a website, I want authorization using an arithmetic task, i.e. the visitor enters the site solves the problem writes the answer, if the answer is correct goes to the site if not, then another task. Tell me how to implement it?

Answer 1

Google how to write a simple captcha, the principle is the same.

Answer 2

myrusakov.ru/php-captcha-math.html