5 children take a group photo, one photo for each two, how many photos are needed in total.
5个小朋友合影，每两人照一张，共需多少张．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">5 / 2</gadget>
<output>5/2 = around 2.5</output>

<gadget id="calculator">4 * (5/2)</gadget>
<output>10</output>

<result>10</result>