Every animal on Farmer Bill's farm is missing one mitten! Children can investigate odd and even numbers as they unravel the missing mittens mystery! The illustrations in this book are funny and cute. There is one picture of Farmer Bill's cow, and she is wearing her on her UDDER! This book is an easy MathStart level 1 book. In MathStart books, pictures do more than tell stories, they teach math. This is a wonderful concept and a great book.