A rectangular pillow cover is 8 decimeters long and 50 centimeters wide, what is its perimeter?
一张长方形的枕巾，长8分米，宽50厘米，它的周长是多少分米
<gadget id="calculator">50 / 10</gadget>
<output>5</output>

<gadget id="calculator">8 + 5</gadget>
<output>13</output>

<gadget id="calculator">13 * 2</gadget>
<output>26</output>

<result>26</result>