It seems like the right thing to do is to think about this for a few moments before she accepts, so Mar does, but it's a good deal.

"That seems fair," she says, and gets out her silver to trade for it. She was already going to be careful with the other books, it's not like she's going to slip up.

Here's some Osirian prince's commentary on the Order of Numbers! It's almost as long as the holy book itself.

This is intimidating! But looking at pieces of it, it's less intimidating than the Order, it's abstract language but it's a fancy academic language rather than can-Abadar-actually-speak-Taldane language.

She'll find somewhere to sit and read about value and trade for a while. Come back for more lessons later.