A square of 4 hectares of land, if the side length increases by 200 meters, how many hectares does its area increase?
一块占地4公顷的正方形土地，如果边长增加200米，它的面积增加了多少公顷？
<gadget id="calculator">200 + 200</gadget>
<output>400</output>

<gadget id="calculator">400 * 400</gadget>
<output>160_000</output>

<gadget id="calculator">160_000 - 90_000</gadget>
<output>70_000</output>

<gadget id="calculator">70_000 / 10_000</gadget>
<output>7</output>

<result>7</result>