In a football match, there are only 6 teams participating in the final stage. These 6 teams will adopt a single round robin match (every two teams will play one game). How many games will these 6 teams play in total?
某次足球比赛，最后决赛阶段只有6支球队参加，这6支球队要采取单循环赛(每两支球队都要赛一场)，这6支球队一共要进行多少场比赛？
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">6 * (5/2)</gadget>
<output>15</output>

<result>15</result>