10 teams participate in a football match, and each team has to compete with other teams. How many games will there be in total?
10个队伍参加足球比赛，每个队伍都要和其他球队比一场，总共要比赛多少场？
<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>