Using "hidden" fields in dynamic form rules

I have a Request form that I need to validate the date and time for the date the service is requested.  I created formula fields to use in the dynamic form rules, but I do not want these fields to be displayed on the form. If I don't include them on the form, the dynamic forms rules don't work.  I tried including them, but for edit only and that did not work either.  I tried putting the formula fields in a separate section and used a dynamic form rule to hide the section and that also caused the date test dynamic rules to fail. 

I have a test form with the fields displayed and the rules work perfectly.  

How can you configure the form so that the fields are not displayed, but they are available to the dynamic form rules? (without using javascript because that is above my skill set.)

Thanks in advance for any help!

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Julie Meeker
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