There are 8 children having a party. When they meet each other, they will shake hands once. How many times will they shake hands in total?
有8个小朋友开联欢会，见面时每两人都要握手一次，一共要握手多少次．
<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>