Storing calculations using Autobind

So I’m trying to use an input field to calculate A x B. And I have set it to autobind with a field in my database. Has anyone had any experience doing this? I have a separate field to do the calculations and my autobinded field points to this field. Doesn’t work unf…

Please note that I am not using the user table but a table I have created.
Any help would be greatly appreciated. Thank you.