There are 4 teams, and there is a game between every two teams, how many games will be played in total.
有4支球队，每两支球队之间都进行一场比赛，一共要进行多少场比赛．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<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>