There are 8 athletes, if every two shake hands once, how many times will they shake hands in total?
有8名运动员，如果每两人握一次手，一共握多少次手．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">7 / 2</gadget>
<output>7/2 = around 3.5</output>

<gadget id="calculator">8 * (7/2)</gadget>
<output>28</output>

<result>28</result>