? text expression to add an numerical constant

Good evening every body,

I intend to get automatically dimensions starting from summary custom (info summary window) toward slddrw sheet. So I created new fields like: length, width and thickness (clicking direct in sheet on concerned dimensions & getting the values, nice !) and I want now to increase them by a numerical constant  value , let say 3/4 inches for each of them, meaning over sized dimensions to be cut before final operation.

Could you tell me the right text expression to be completed in VALUE / TEXT / EXPRESSION ?, so manner to get the right total . You'll better see this, if you open the atachment showing in detail what exactly happen ! I hope this explain you good enough my trouble, and will be easier to you to come with the answer. I tried following the same rule as in Excell using F4 touch bringing \\\$\\\$ (and keep this numerical constant fixed, but is not the case,  not programming (Visual Basic ?)). May be Solidwork use another ?! (by the way, wich one ?)

Thanks again and enjoy the new year 2018, comming soon

ps:  Hope my written english (not my most fluent language I know) is understandable.

Dan Aninaru

SolidworksEducator Student