If the length and width of a rectangle are increased by 2 cm respectively, what is the increase in the perimeter of the rectangle by how many cm?
一个长方形的长和宽分别增加2厘米，这个长方形的周长增加多少厘米．
<gadget id="calculator">2 * 4</gadget>
<output>8</output>

<result>8</result>