There are 4 students playing table tennis, if there is a game between every two students, how many games will be played in total?
有4个同学进行乒乓球比赛，如果每两名同学之间都进行一场比赛，一共要进行多少场比赛．
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

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

<gadget id="calculator">3 * 2</gadget>
<output>6</output>

<result>6</result>