Use 6 sticks of 3 cm each to form a rectangle, what is the perimeter of the rectangle in cm?
用6根都是3厘米的小棒摆成一个长方形，这个长方形的周长是多少厘米．
<gadget id="calculator">6 * 3</gadget>
<output>18</output>

<result>18</result>