Given that the length of the rectangle is 9 cm and the width is 7 cm, what is the perimeter?
已知长方形的长是9厘米，宽7厘米，求周长？
<gadget id="calculator">9 + 7</gadget>
<output>16</output>

<gadget id="calculator">16 * 2</gadget>
<output>32</output>

<result>32</result>