6 students have a wrestling match, two of them will have a match, how many games will there be in total?
6名同学进行摔跤比赛，每两个人都要进行一场比赛，一共要比赛多少场．
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">6 * (5/2)</gadget>
<output>15</output>

<result>15</result>