What is the perimeter of a rectangle 3 decimeters long and 20 centimeters wide?
长3分米，宽20厘米的长方形的周长是多少分米
<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<gadget id="calculator">30 + 20</gadget>
<output>50</output>

<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">50 * (1/5)</gadget>
<output>10</output>

<result>10</result>