A door is 210 cm high and 90 cm wide, what is the perimeter of the door in cm?
一扇门高210厘米，宽90厘米，这扇门的周长是多少厘米．
<gadget id="calculator">210 + 90</gadget>
<output>300</output>

<gadget id="calculator">300 * 2</gadget>
<output>600</output>

<result>600</result>