The Wishing Club: a story about fractions by Donna Jo Napoli, pictures by Anna Currey.
When Petey wishes on a star for a dollar, he ends up finding a quarter instead. His little brother wishes for a cookie, but gets half a cookie instead. His twin sisters each wish for a bag of marbles and each ends up with 10 marbles, 1 eighth of a bag. The star turns out to be a comet and on the final day it will be visible, the children come up with a plan to put their fractions together into one big wish to get one whole thing.
So many math-based picture books are more about the cleverness of the math than the quality of the story, but Napoli has created a math book with heart and magic. A large part of it is the strength of her writing and the wonder of the characters at what is happening. The illustrations work with this wonder in their soft washes that make it seem as if anything is possible.
Highly recommended for classrooms working with fractions, this book works well as a read-aloud at any time. Appropriate for ages 4-7.