4 teams, each with a game between 2 teams. How many games did the whole group play?
4支球队，每2支球队之间都进行一场比赛．整个小组共赛多少场．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2)</gadget>
<output>6</output>

<result>6</result>