<p>I'm on the Activities Section of the Common App, and I see it says to list the activities "in their order of importance to you". </p>
<p>For two years now, I've participated with a group in this annual 13-hour mathematics challenge. I'm not sure if it counts as an extracurricular because it seems like they want activities in which you devoted your time weekly. My group never did actual scheduled training sessions. We just generally learned new concepts in math class that could possibly help us solve whatever problem was going to be thrown at us for the competition. </p>
<p>It is definitely a very important activity for me--I was even thinking about using it as the topic of my choice for the Short Answer part of the Writing Section.</p>