The perimeter of a square field is 800 meters, and the harvest of rice per hectare is 7.5 tons, so how many tons of rice can be harvested in this land?
一块正方形地的周长是800米，每公顷收稻谷7.5吨，那么这块地收稻谷多少吨？
<gadget id="calculator">800 / 4</gadget>
<output>200</output>

<gadget id="calculator">800 / 4 / 10_000</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">7.5 * 200 * (1/50)</gadget>
<output>30</output>

<result>30</result>