Anno's Mysterious Multiplying JarReview posted January 21, 2013.
Philomel Books, New York, 1983. 44 pages.
Starred Review
2012 Sonderbooks Standout: #7 Children's Nonfiction
How did I not know about this book?! How did I not know there is a picture book that explains factorials?! It was written before my boys were born -- and I didn't know to buy it for them! This is a crime!
I was at the library, refilling our display of children's nonfiction books. I find that if I put out children's math books, they get snapped up. I make sure to put out fun children's math books, like anything by Greg Tang, or A Million Dots, by Andrew Clements, or Piece = Part = Portion, by Scott Gifford. But while I was looking through the 510s for good fun math books, I found Anno's Mysterious Multiplying Jar.
The idea is simple. Mitsumasa Anno and his son show us a jar that contains a sea and an island. Each island has 2 countries. Each country has 3 mountains. Each mountain has 4 walled kingdoms. In each kingdom are 5 villages. In each village are 6 houses. In each house are 7 rooms. In each room are 8 cupboards. In each cupboard are 9 boxes. And within each box, there are 10 jars.
How many jars are there all together? There are 10! = 10 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 = 3,628,800. The second half of the book shows this even more clearly, using dots. And there's an afterword as well, that explains some of the further uses of factorials.
It's so simple. So beautiful. And it explains factorials! To children! Yes!