The way that gods do math is not at all like the way humans do.
It took the Shadowgod a very long time, with Leareth, to even figure out how to translate it; it required an addition to the avatar, specially designed to work with Leareth and translate those concepts in particular, pulling them directly out of his head, it's the only way to get dense enough communication and gods don't speak math notation.
(It gives Leareth headaches, unlike the standard, less - directly mindreading - avatar. It's in a different room, so that no one else can plug into it by accident, especially Belrun who is understandably leery of a god reading her mind.)
And then the effortful translation back, piece by piece.
The Shadowgod finds nothing wrong that would have led to disaster. Suggests some tweaks, where something would have had not quite the result Leareth wanted or predicted, without changing the final outcome too much.
It takes them years.