If the length and width of a rectangle are increased by 5 centimeters, its perimeter will increase by how many centimeters.
一个长方形长和宽各增加5厘米，它的周长就会增加多少厘米．
<gadget id="calculator">5 + 5</gadget>
<output>10</output>

<gadget id="calculator">10 * 2</gadget>
<output>20</output>

<result>20</result>