The perimeter of a square is 12 meters, if the side length increases by 2 meters, its area will increase by how many square meters.
一个正方形的周长是12米，边长如果增加2米，它的面积就会增加多少平方米．
<gadget id="calculator">12 / 4</gadget>
<output>3</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<gadget id="calculator">3 * 3</gadget>
<output>9</output>

<gadget id="calculator">25 - 9</gadget>
<output>16</output>

<result>16</result>