Chess should be taught as an after-school activity because it will help students learn how to use their time wisely, and how to work well under time pressure. 

It is a game where two people attempt to outwit each other with their pieces on the board. It involves logical thinking, teaches you how to make decisions, helps train your memory, and strengthens your willpower.

Chessboards are cheap. It costs thirty dollars for five chess sets.

Players receive rigorous mental workouts, resulting in better brain function. Strategic thinking forces you to develop certain strategies and plans to use on your opponent to win.

Chess will help your brain in many ways. For example, you become more attentive during the game because you need to pay attention to every single move that is made by both sides. 

The game trains your brain to think carefully, but at a steady pace with time pressure which is similar to how schools administer tests.