Notes 6 is a blank Circle of Fifths chart which I pass out to my students. For your convenience, I have added both the blank student handout and the teacher copy with the answers.
We fill these out as a class, with the piano as our visual guide.
As far as instruction and practice, it's up to you if you want to have your students memorize this and drill it into them. I personally chose to not do this; instead, I offered it as another way to show how and why key signatures work the way that they do. For some students, this helped it "click"; for other students, it didn't make as much sense. Between Unit 5 and 6, however, all students should grasp the concept of scales and key signatures.