If there is a table tennis match between two people, how many games will the 5 students play in total?
每两个人之间进行乒乓球比赛，5名同学一共要比赛多少场．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

<gadget id="calculator">4 * (5/2)</gadget>
<output>10</output>

<result>10</result>