Uncle Wang’s family has a rectangular vegetable plot with a length of 20 meters and a width of 10 meters. After the expansion, the length and width of the plot increased by 5 meters and 2 meters. How much did the area of the vegetable plot increase?
王大伯家有一块长方形菜地长20米，宽10米，扩大后长增加了5米，宽增加了2米，菜地面积增加了百分之几？
<gadget id="calculator">20 + 5</gadget>
<output>25</output>

<gadget id="calculator">10 + 2</gadget>
<output>12</output>

<gadget id="calculator">25 * 12</gadget>
<output>300</output>

<gadget id="calculator">20 * 10</gadget>
<output>200</output>

<gadget id="calculator">300 - 200</gadget>
<output>100</output>

<gadget id="calculator">100 / 200</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>