There are 4 football teams playing football, and every two teams play one game, how many games will be played in total.
有4个足球队踢球，每两个队踢一场，一共要踢多少场．
<gadget id="calculator">3 / 2</gadget>
<output>3/2 = around 1.5</output>

<gadget id="calculator">4 * (3/2)</gadget>
<output>6</output>

<result>6</result>