If the side length of a square is x cm, if the side length is increased by 10 cm, then the perimeter will increase by how many cm.
一个正方形的边长是x厘米，如果边长增加10厘米，那么周长将增加多少厘米．
<gadget id="calculator">10 * 4</gadget>
<output>40</output>

<result>40</result>