Format output of confirmation rule

Hi

I am getting some large numbers out of my confirmation rules and I am looking for ways to format the output so it is easier to read. Preferably commas between the thousands, millions, billions... etc but would also like to know what other formatting options are available as well.

 

Currently my output is the below and I am trying to make the 'math.Round(Acc1,2)' part easier to read.

 

Does anyone know of a resource that lists the different formatting options? 

Or just how to add the comma seperators?

 

Thanks

Simon