Book knowledge is the ability to recognize book formats and purpose. Early readers learn how to hold a book properly, to read English from left to right, how pictures supplement the story, and that books have basic components such as a front and back, spine, pages, covers, and more. Children automatically learn these things at a conceptual level long before they understand the purpose of each component.
With adaptive learning, the programs won't move on to the next level until your child has a firm grasp on the current material. The online games will be a wonderful way for your child to catch up on basic arithmetic concepts and be comfortable using them across applications.
Since 3rd grade math relies on the concepts that were learned during kindergarten, first and second grades, don't be afraid to start your child at a lower level.
Keep preschool writing activities relaxed and fun. Don't expect or require perfection. Learning to write is a fun process that will give your preschooler a boost in confidence and solid foundation for future studies.