A rectangular vegetable field has a circumference of 1800 meters and a length of 500 meters. If 850 kilograms of vegetables are harvested per hectare, how many kilograms of vegetables can this field harvest?
一块长方形菜地，周长是1800米，长是500米，如果每公顷收菜850千克，那么，这块地能收菜多少千克？
<gadget id="calculator">1_800 / 2</gadget>
<output>900</output>

<gadget id="calculator">900 - 500</gadget>
<output>400</output>

<gadget id="calculator">400 / 10_000</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">850 * 500 * (1/25)</gadget>
<output>17_000</output>

<result>17_000</result>