How many hectares are there in a square wheat field with a side length of 400 meters? how many hectares
一块边长是400米的正方形麦地，有多少公顷？多少公顷
<gadget id="calculator">400 * 400</gadget>
<output>160_000</output>

<gadget id="calculator">160_000 / 10_000</gadget>
<output>16</output>

<result>16</result>