Hello @zougou !
I trust you’re doing well today!
For anti-spam purposes we generally suggest using the Captcha field which seems to be much better than other solutions, especially hCaptcha: https://wpmudev.com/docs/wpmu-dev-plugins/forminator/#captcha-field
There’s also an option to enable Honeypot protection which creates a hidden field that bots will try to fill in and if they do, Forminator will reject the submission: https://wpmudev.com/docs/wpmu-dev-plugins/forminator/#security
And if you’re using Akismet, Forminator has an integration with it as well, the details are available under the same link above.
You can create a simple solution of this kind using the fields and conditional rules, however there’s currently no way to generate the equations. Here’s how you could set the scenario:
Create a Number field: https://monosnap.com/file/CjTyyBmbH6qbusyNikPNvEOkxKjm80
Go to the submit button settings: https://monosnap.com/file/W4ue30d6CSkuBH4xGjFlKzbZY10uDC
Set the Visibility of the Submit button to only show if the solution to the equation is correct: https://monosnap.com/file/pvCF3hsP1qJujhtr4cbbwZxnzuHVqv
Hope this helps!
Kind regards,
Pawel