There are 15 A-A football teams playing a double round-robin game (two games for each team), how many games will be played in total?
有15只甲A足球队，进行双循环比赛(每两支队赛两场)，共要举行多少场比赛？
<gadget id="calculator">15 - 1</gadget>
<output>14</output>

<gadget id="calculator">14 * 15</gadget>
<output>210</output>

<result>210</result>