We used The Twenty-One Balloons for our 6th grade readers. We paired this with the math adventure book Sir Cumference and the Viking’s Map by Cindy Neuschwander. We have also used this novel with our high reading 5th graders and low reading 7th graders. The CCSS noted in this activity guide are for 6th grade. Please download our FREE introduction to Book Study Buddies for more information on this project.