A rectangular field is 250 meters long and 160 meters wide. How many hectares is this farmland?
一块长方形的耕地，长250米，宽160米．这块耕地有多少公顷．
<gadget id="calculator">250 * 160</gadget>
<output>40_000</output>

<gadget id="calculator">40_000 / 10_000</gadget>
<output>4</output>

<result>4</result>