For a 1-hectare square vegetable plot, when the side length is increased by 50 meters, how many square meters does the vegetable plot area increase?
一块1公顷的正方形菜地，边长增加50米后，菜地面积增加了多少平方米？
<gadget id="calculator">100 + 50</gadget>
<output>150</output>

<gadget id="calculator">150 * 150</gadget>
<output>22_500</output>

<gadget id="calculator">100 * 100</gadget>
<output>10_000</output>

<gadget id="calculator">22_500 - 10_000</gadget>
<output>12_500</output>

<result>12_500</result>