There are 10 students participating in a table tennis competition, and every two students will play one game. How many games will there be in total?
有10名同学参加乒乓球比赛，每两名比赛一场，一共要比赛多少场．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">9 / 2</gadget>
<output>9/2 = around 4.5</output>

<gadget id="calculator">10 * (9/2)</gadget>
<output>45</output>

<result>45</result>