you will get arithmatic sum with answer you just have to compare with ur user in controller

Repackaged visualCaptcha's backend service, including translation and minor modification. Mainly for private use. Everything still belongs to original author: emotionLoop. ...

Gem that uses RuCaptcha API to solver any type of captcha

Integrate the AreYouAHuman.com CAPTCHA alternative human verification into your Ruby/Rails application

Implementation of captcha (Completely Automated Public Turing-Test to Tell Computers and Humans Apart) that is both easy to use and easy to customize/extend.