Teaching Maths through stories can be hugely rewarding and impactful. It promotes talk, just as you would when reading a normal book - asking comprehension, inference and prediction questions as you go. It can also serve as a great hook for some story-themed Maths activities once the book is over - often reeling in those learners who are resistant to Maths lessons, but LOVE a good story!
Maths story books also champion the notion that Maths should not be seen in isolation as an abstract set of skills. What we learn in Maths can be applied to all sorts of every day activities - and Maths story books help to show where and how Maths can be used in real-life problems and situations.