There are 7 players playing table tennis, if every 2 players play a game, how many games will there be in total?
有7名运动员进行乒乓球比赛，如果每两位运动员进行一场比赛，一共要比赛多少场？
<gadget id="calculator">42 / 2</gadget>
<output>21</output>

<result>21</result>