The Parents’ Guide to Student Success guides were developed to support the Common Core State Standards. Created by teachers, parents, education experts, and others from across the country, the standards provide clear, consistent expectations for what students should be learning at each grade to be prepared for college and career. National PTA created the guides for grades K–8 and two for grades 9–12 (one for English language arts/literacy and one for mathematics). In all, 11 guides were created.

Here is a link to the 8th grade guide:

Parents' Guide to 8th Grade ELA and Math