If the length of the rectangle is increased by 5 cm and the width by 2 cm, the perimeter will be increased by how many cm.
长方形的长增加5厘米，宽增加2厘米，周长增加多少厘米．
<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">7 * 2</gadget>
<output>14</output>

<result>14</result>