A square open-air garbage dump with a side length of 400 meters is reduced by 100 meters after renovation. How many hectares does this garbage dump now occupy?
一个边长为400米的正方形露天垃圾场，经改造后边长减少了100米，现在这个垃圾场占地多少公顷？
<gadget id="calculator">400 - 100</gadget>
<output>300</output>

<gadget id="calculator">300 / 10_000</gadget>
<output>3/100 = around 0.03</output>

<gadget id="calculator">300 * (3/100)</gadget>
<output>9</output>

<result>9</result>