In 2024 you still can't copy a calculated cell from Numbers into Pages.

You can't copy a Numbers calculated cell, like one formed by concatenating strings in other cells, into Pages. The formula is pasted instead, typically with an error icon (absent references). It's apparently been a problem for all eternity, though I just ran into it recently.

There's some kind of shades-of-macOS Classic Publish/Subscribe paste functionality that works if the Numbers source is non-calculated. But that functionality breaks calculated cells.

The workaround is to paste into something like Notes.app or TextEdit.app or pretty much anything but Pages. Then copy/paste that into Pages.