The Annos demonstrate the concept of factorials. Inside a mysterious jar, there is some water, which becomes a sea. In that sea, there is an island, and so on until the reader has counted to 3,628,800!
"Superbly demonstrating the conception of factorials in mathematics, the text and pictures combine to present a lesson in a palatable form as well as the pleasure of looking at pictures that only Mitsumasa Anno could invent." — Publishers Weekly
"The book moves logically and elegantly from the concrete to the abstract. Once made clear, the concept is unforgettable, but the book entices the reader to return for further appreciation of the artistry with which it was designed." — The Horn Book
"If you want a book that does a good selling job on the factorial concept, this one works." — School Library Journal