This is a good way to help students see the main idea of a nonfiction piece. It also helps them summarize a story so they can use this paper to reference the work later without searching the entire document again. Finally, it is a good way to show them that all good work has main points that are supported by details.
A Reading Strategies Lesson: Finding Details and Writing Summaries
Upper Elementary Snapshots: Summarizing More
Eclectic Educating: Nonfiction Summary - like the nonfiction tips
Great anchor chart for Summarizing. This 4th grade teacher has a ton of good ideas!
Summarizing/ could use to sum up an art lesson. A quick exit quiz for checking retention of info
YoungTeacherLove: Reading and Summarizing Nonfiction: Coding the Text! An awesome strategy to help your kids break down nonfiction.