Richard Evan Schwartz. It is a book about numbers. It goes from 1 to 100 and each number is represented by a monster. For each number there is a factor tree that goes down to the lowest factor for the given number.
This is such a fun book to learn about numbers and factoring. The author, Richard Evan Schwartz, is a math professor at Brown University and put this book together to help his two daughters understand prime numbers. This book is very creative and a visual way to learn math.
The publisher's put the age range for this book as 4-8. I know that my friend has a 4-year-old daughter and they have really enjoyed looking at this book together. Flip through this book at a bookstore and you will find a fun way for children to visually grasp prime numbers.