I use this when I am teaching divisibility. Divisibility rules are crucial in long division and reducing fractions to lowest terms. The kids LOVE it! I put the desks in groups, and place a Divisibility Rule on each group. As the students enter my room, I give each on a card with a number on it, and they have to find the appropriate table. If they are struggling, I encourage them to ask the people already sitting whether they belong to that group. We do it several days in a row. Not only are the kids learning the divisibility rules, they are sitting with different students each day, and I have a quick formative assessment of who knows the rules and who doesn't. Awesome activity!!