The conditional calculation field on my form isn't working. The fields are missing from the preview.

I am trying to calculate 4 fields and add them up into the fifth field. I want the fifth field to be "read-only" and possibly greyed out so people filling out the form know they don't need to fill it out.

I haven't uploaded the form yet, as it's not working.

I've tried a couple of different methods including several widgets. What am I doing wrong?

The screenshot is of the missing fields.

Edit: Sorry, I didn't explain myself well. Those fields are in the form I've created but aren't appearing if I publish the form. This is the conditional calculation I have set for those fields:

I am not able to find the fields from the screenshot on the form that you have provided. However, you may mark a field as read-only from the Advanced section of the field properties. 

Hope this information helps! Please get back to us if you need any further assistance. We will be happy to help. 

Thanks for your response, but I didn't explain myself well. I have edited the question with a new screenshot.

You do not actually need a condition to achieve that. You just have to use the form calculation widget as the 5th field then add the fields in the calculation wizard.

Example:

If you want the calculation widget field to be read-only, click the 3 dots below the numbers found in the calculation wizard. Go to Options tab then check Result field is read only.  See screenshots below:

Hope this helps!

Sorry, here's the demo form: https://form.jotformpro.com/71379033694968

You can clone this form if you want http://www.jotform.com/help/28-Cloning-a-Form-from-a-Web-Page.