Trudy Harris 
20 Hungry Piggies [PDF ebook] 
A Number Book

Nearly everyone has heard about the little piggy that went to the market and the one that stayed home-but there’s a lot more to the story! 20 Hungry Piggies completes the tale while, unbeknownst to the reader, teaching an important math concept at the same time. There are many counting books that deal with cardinal numbers (1, 2, 3, etc), but this book teaches ordinal numbers as well-an important part of the kindergarten math curriculum. As an added bonus, children will have a great time trying to find the hidden wolf and hidden numbers in each spread.