There are 12 teams participating in a volleyball league, and a single round-robin match is adopted (every two teams play one game), how many games will be played in total?
一次排球联赛共有土12支队伍参赛，采取单循环赛(每两支球队间进行一场、比赛)，一共要进行多少场比赛？
<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>