A rectangular nursery is 5 meters long and 3 meters wide. A fence surrounds the nursery. How long is the fence?
一个长方形苗圃，长5米，宽3米，在苗圃四周围一圈篱笆，篱笆长多少米？
<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">8 * 2</gadget>
<output>16</output>

<result>16</result>