Uncle Zhang has a rectangular vegetable field with a length of 50 meters and a width of 0.04 kilometers. What is the area of this vegetable field in hectares?
张大伯有一块长50米，宽0.04千米的长方形菜地，这块菜地的面积是多少公顷？
<gadget id="calculator">50 / 10_000</gadget>
<output>1/200 = around 0.005</output>

<gadget id="calculator">0.04 * 1_000 * (1/200)</gadget>
<output>0.2</output>

<result>0.2</result>