If 8 students meet each other, if every two people shake hands once, how many times will they shake hands in total?
8个同学见面，如果每两个人握一次手，一共要握多少次手．
<gadget id="calculator">8 - 1</gadget>
<output>7</output>

<gadget id="calculator">8 / 2</gadget>
<output>4</output>

<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<result>28</result>