By Emily Pearson
An ordinary girl leaves a bucket of blueberries on a neighbor's step, and the book multiplies that one small thing by five, and five again, until it has gone round the world and come back to her.
Mary is an ordinary girl having an ordinary day. She finds blueberries, picks them, and leaves them on Mrs. Bishop's doorstep without saying who they're from. Mrs. Bishop bakes them into muffins and gives them to five people. One of those is Mr. Stevens, who helps five people with their luggage. One of those is Maria, who does something for five more. And the book keeps going: five, twenty-five, a hundred and twenty-five, six hundred and twenty-five, on and on across the world, until the numbers are enormous and the last one loops all the way back round to Mary's own front step.
Be straight with yourself about what this is: the chain is the engine and Mary is barely a character. She does one thing on page two and then vanishes until the end, and nobody in the queue after her is anyone in particular. That's a real limitation if you wanted a story. It is also exactly why the book works where it works — as a math lesson your class doesn't notice is a math lesson. Multiplying by five is abstract on a worksheet and completely concrete when the fifth round of it is a crowd of people spilling off the page. Bright, uncomplicated art, nothing to brace for, five minutes start to finish. Use it for the number, and let a different book do the feeling.