Three classes in the fourth grade hold a tug-of-war competition, and every two classes have to compete once, so how many games will there be in total?
四年级3个班举行拔河比赛，每两个班都要比赛一场，则一共要比多少场．
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">2 * (3/2)</gadget>
<output>3</output>

<result>3</result>