The side length of a square is 4 cm. If the side length is increased by 2 cm, how much square centimeters will the area be increased?
正方形的边长是4cm，如果边长增加2cm，则面积增加多少平方厘米．
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<gadget id="calculator">4 * 4</gadget>
<output>16</output>

<gadget id="calculator">36 - 16</gadget>
<output>20</output>

<result>20</result>