Adobe Forms subtotal with formcalc

Hi,

i am trying to get a subtotal of a page and a total at the end of a 100 lines table. 

I've tried using this: 

The total sum i would get with sum(....). 

But the for the Subtotal sum i need the pagecontent to get the subtotal at every Page until the last page, where i need the total. 

How can i realise this? Because there is not much information right here: https://help.adobe.com/en_US/livecycle/10.0/DesignerScriptingRef/WS92d06802c76abadb-3e14850712a151d2...