5 classmates take pictures, if everyone wants to take a group photo, how many photos will be taken in total.
5个同学照相，如果每个人都要拍一张合影，一共要拍多少张相片．
<gadget id="calculator">5 - 1</gadget>
<output>4</output>

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

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

<result>10</result>