Math Captcha in Register Forms
Math Captcha allows you to use simple math problems to test site users to prove their human identity. You can read the installation guide here.
Once the plugin is activated, it is automatically enabled. Go to your site's registration page to check and test the Math Captcha.
If you want to change the width of the Math Challenge text field, you can try and use the CSS code below:
Warning: We have created this code example to provide guidance and to make it easier for you to implement this code into your website. However, we are not able to provide any support when it comes to customizing the plugin. If you need help implementing this code, please hire a developer.