This is a simple add-on for
Restrict Content Pro that adds a math verification field to the registration form, which helps to prevent bot registrations while also not driving your users crazy with difficult to read reCaptchas.
With this add-on, you can add a simple math verification field to your membership registration form. In order to signup, the user must complete the simple addition problem.
This add-on is designed to completely prevent bot registrations, while still presenting a very human-friendly and easy-to-use registration process, unlike the experience users have when trying to fill out difficult-to-read reCaptchas.