square vegetable field has a side length of 800 meters, what is the area of the vegetable field in hectares?
一块正方形菜地，边长是800米，这块菜地的面积是多少公顷．
<gadget id="calculator">800 * 800</gadget>
<output>640_000</output>

<gadget id="calculator">640_000 / 10_000</gadget>
<output>64</output>

<result>64</result>