Upper Elementary Book Review discussion

This book is written on a 3.4 reading level, yet I think it can hold the interest up to fifth grade (might even push sixth grade). This is the battle of a brother and sister who normally do everything together but through a series of unfortunate events and misunderstandings, end up in a contest to see who can make the most money selling lemonade. This book also interweaves some great math lessons as well as entrepreneurial vocabulary. Excellent book! (It's part of a series, which might also keep kids reading.)