Eight students participate in the table tennis trials. If every two students must play one round, how many rounds should they play in total?
8名同学参加乒乓球选拔赛，如果每两人必须打一局，一共要打多少局．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">8 * (7/2)</gadget>
<output>28</output>

<result>28</result>