Explain that rules exist to keep people safe and treat people fairly, and give a real home rule as an example.
Rules are things we agree to do so everyone stays safe and things stay fair. Your home has rules. Your school has rules too.
Some rules keep you safe, like holding a grown-up's hand near cars. Some rules keep things fair, like waiting your turn.
Mastery looks like: They can name a real household rule and explain whether it is mainly about safety, fairness, or both.
Common stumbles: Seeing rules as arbitrary limits rather than protections is common at this age; connecting each rule to a real reason helps it click.