The lion's share by Matthew McElligott

A and C Black, 2012. ISBN 1408173883.
(Ages 4+) Highly recommended. Maths themes. Picture book.
When the lion, the king of the beasts, invites his friends to dinner, the ant is rather concerned, as she has never been invited before. After a sumptuous dinner where the animals all behave rather badly (except for the ant), the lion brings out a large cake to eat. Elephant takes half then pushes the rest on to the hippo, who takes half of what is left, then pushes the rest on to the gorilla who takes half of what is left, and so on. Each animal takes half of what is left on the plate when it gets to him. At the end of the line is the ant and when the cake comes to her she tries to cut what is left in half, but succeeds in only making crumbs. She is berated by the other animals for being greedy, so she apologises to the lion, saying she will bake him a special cake and bring it along the next day.
The other animals, not wanting to be outdone, promise cake to the lion, each doubling what they offer in turn. By the time the offer gets to the elephant, doubling each time, the elephant must bake 256 cakes.
Each of the animals is depicted in almost sepia tones, the cutting up of the cake adding colour to the pages. The endpapers give a more mathematical look at the cutting of the cake, something which could be emulated in the classroom. Children will delight in the figures of each of the animals, and ponder the fun of the subtitle, 'a tale of halving cake and eating it too'.
This is an extremely funny look at fractions and sharing of numbers through the cutting up of a cake, then the doubling and redoubling of the number one. Apart from being a funny read with absolutely delightful illustrations, the story would be a great introduction to the idea of fractions and numbers.
Fran Knight