I tired the math mathods like Math.Floor, / and Math.Round. But these output nodes are not supported. I am unsure of what type of nodes are supported. However, I do know that the only method that works is list.count.
Take the count out of a list (flatten) and put it in a renamed watch node. Generative Design can’t use lists as outputs because it needs to be a single number for each design option in order for the optimization to try to minimize it or maximize it…also for it to show what the output is in the charts etc for each design.