There are 8 people participating in a chess match. If there is a match between each of them, how many games will there be in total?
有8人参加象棋赛，如果每两人之间都要比赛一场，一共要比赛多少场．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<result>28</result>