What's the trick to thinking logically?

Top things to learn on Khan Academy this week:

• Presidents' Day: Why does the U.S. have presidents instead of a king?
• How does financial aid for college work?
• What's the trick to thinking logically?

Just added from the California Academy of Sciences:

• Where is the largest biodiversity hotspot in the United States?

This is an informational email from Khan Academy.

• Subject: Learn something new at Khan Academy
• Sender: Registered user of Khan Academy
• Frequency: Emails are sent approximately every 2 weeks.
• Action: An option to unsubscribe is provided.
• Address: P.O. Box 1630, Mountain View, CA 94042