A rectangular salt field with an area of 10 hectares has a width of 200 meters and a length of 200 meters.
面积为10公顷的长方形晒盐场，宽是200米，长是多少米．
<gadget id="calculator">10 * 10_000</gadget>
<output>100_000</output>

<gadget id="calculator">100_000 / 200</gadget>
<output>500</output>

<result>500</result>