There are 12 players in a sports competition. If every two people shake hands once, how many hands will they shake?
一场体育比赛中，共有12名运动员．如果每两个人握一次手共握多少手．
<gadget id="calculator">12 - 1</gadget>
<output>11</output>

<gadget id="calculator">11 / 2</gadget>
<output>11/2 = around 5.5</output>

<gadget id="calculator">12 * (11/2)</gadget>
<output>66</output>

<result>66</result>