There are five classes in the sixth grade in a basketball game, and every two classes have a game. How many games are there in total?
六年级5个班进行篮球比赛，每两个班进行一场比赛，一共进行多少场比赛．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 * (5/2)</gadget>
<output>10</output>

<result>10</result>