I don't get the point of structuring a textbook in this way. It seems like a huge waste of time if you just want to quickly learn some stuff.
If I were a child, I would absolutely detest having learning material wrapped up in a story like that (with the obvious exception of learning about literature itself).
But if you want to entertain yourself, and you enjoy both reading and maths? We haven't tried Fred, but DS loves Lucy and Stephen Hawking's George books, which do something similar with physics.
