Anybody can use the entire Khan Academy for free.  We don’t have any starting guidelines based on grade level or age; instead we encourage users to explore.  Here are a few areas to check out:  

1. Videos: Explore our new and noteworthy section or search for a specific video.  

2. Practice your skills using the exercise dashboard.  Start at Addition 1 or explore on your own.  We especially like these exercises: 

• Inequalities on a number line
• Understanding decimals place value
• Derivative intuition

3.  Profiles:  Log in to see your badges, track your learning progress, or to coach.  

Related links:

• How do I set-up a new user account?
• I'm a teacher, coach or parent, how do I start using the site with my students?
• I'm a school administrator considering a pilot in my school, where do I begin?
• What is a coach?
• Khan Academy Teacher Toolkit