The product is a lot of four books by Danica McKellar, including one hardcover and three paperback editions. The books are part of the Math Lot series and focus on mathematics. Written in English and published by Plume in the United States, these nonfiction books are authored by Danica McKellar and cover various topics related to mathematics. Ideal for readers interested in learning more about mathematics, this lot offers a diverse selection of books by a well-known author in the field.