The .currentpage and .totalpages functions display, respectively, the current index (beginning from 1) of the page/slide the function call lies in and the total amount of pages/slides. They don't accept any argument.

They are unsupported in plain documents, where the - placeholder is shown instead.

[!NOTE] These functions return visual elements (nodes), not numbers. Hence, it is not allowed to do, for example, .sum {.currentpage} {3}.

Fixed page counter

A page counter can be displayed on each page thanks to page margin content:

.pagemargin {bottomcenter}
  .currentpage / .totalpages