Dehui Primary School holds a basketball game. There are a total of 9 participating teams. There is a game between every two teams. How many games are there in total?
德惠小学举行篮球比赛，一共有9个参赛队，每两个队之间都要进行一场比赛，共要进行多少场比赛．
<gadget id="calculator">9 - 1</gadget>
<output>8</output>

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

<gadget id="calculator">9 * 4</gadget>
<output>36</output>

<result>36</result>