Xiao Ming, Xiao Hong, Xiao Liang, Xiao Gang, Xiao Qiang, and Xiao Li are playing a chess game. If each of them has to play one game, how many games will they play in total?
小明、小红、小亮、小刚、小强和小丽6人进行象棋比赛，如果每两人都要赛一盘，那么一共要赛多少盘？
<gadget id="calculator">6 - 1</gadget>
<output>5</output>

<gadget id="calculator">6 / 2</gadget>
<output>3</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<result>15</result>