There are 10 students playing a game of Go. If every two students have to play one game, how many games will there be in total?
有10名同学进行围棋赛，如果每两名同学都要比赛一场，一共要比赛多少场．
<gadget id="calculator">10 * 9</gadget>
<output>90</output>

<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<result>45</result>