A piece of rectangular land with a perimeter of 280 meters, the ratio of length to width is 5:2, if the average yield of wheat per hectare is 5250 kg, and the flour yield is 80%, how many kilograms of flour can be processed from the wheat harvested on this land ?
一块周长是280米的长方形土地，长与宽的比是5：2，如果平均每公顷土地产小麦5250千克，按出粉率80%计算，这块土地上收的小麦可以加工面粉多少千克？
<gadget id="calculator">5 + 2</gadget>
<output>7</output>

<gadget id="calculator">280 / 2 / 7</gadget>
<output>20</output>

<gadget id="calculator">2 / 10_000</gadget>
<output>1/5_000 = around 0.0002</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">5_250 * 20 * 5 * 20 * (1/5_000) * (4/5)</gadget>
<output>1_680</output>

<result>1_680</result>