If the length of a rectangle is 3 decimeters and the width is 2 decimeters, what is its perimeter?
一个长方形的长是3分米，宽2分米，它的周长是多少．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

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

<result>10</result>