In a party of 8 people, every two people shake hands once, how many times should they shake hands in total?
8人聚会，每两人握手一次，一共要握手多少次．
<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>