How to sum together many Global Properties

I want to automate upkeep and so I need something to be able to set one Global Property by summing a number of different Global Properties. I don’t know how to build an expression that grabs a bunch of numerical properties and then does maths to them (including multiplying something by two before adding it to the sum).
At the moment I’m doing this with multiple “Set Global Property” actions, which doesn’t seem the most elegant way to go about it.

I put it together. The answer, of course, was to use a lot of brackets and the GetProperty command. eg {(((GetProperty(“Property 1”))*2)+((GetProperty("“Property 2”))}. though tracking all those brackets makes my head swim a bit.

Calculated Properties seem easier to use, though the documentation for them is only in the Editor help and not on this site’s wiki.