Math Captcha (wp-math-captcha) free WordPress plugin

Math Captcha is a 100% effective and easy to use CAPTCHA for WordPress that seamlessly integrates into login, registration, lost password, comments, bbPress and Contact Form 7.

For more information, check out the plugin page or see the Support Forum.

Features include:

• Select where to use math captcha: login, registration and lost password forms, comments, Contact Form 7 and bbPress
• Hiding captcha for logged in users
• Select which mathematical operation to use
• Displaying captcha as numbers and/or words
• Multiple captcha on one page support
• Block spambots direct access to wp-comments-post.php
• Option to set captcha field title
• Option to set captcha input time
• .pot file for translations included