The base of a parallelogram is 6 cm and the height is 2 cm. If the base remains the same and the height increases by 2 cm, how much does the area increase?
一个平行四边形的底是6cm，高是2cm，如果底不变，高增加2cm，则面积增加多少．
<gadget id="calculator">2 + 2</gadget>
<output>4</output>

<gadget id="calculator">6 * 4</gadget>
<output>24</output>

<gadget id="calculator">6 * 2</gadget>
<output>12</output>

<gadget id="calculator">24 - 12</gadget>
<output>12</output>

<result>12</result>