A highway team repairs a road. If it repairs 400 meters per day, it will be completed 1 day ahead of schedule. If it repairs 500 meters per day, it will be completed 2 days ahead of schedule. How long is this road in meters?
某公路队修一条公路，如果每天修400米，则比计划提前1天完成，如果每天修500米，则比计划提前2天完成，这条公路长多少米？
<gadget id="calculator">2 - 1</gadget>
<output>1</output>

<gadget id="calculator">1 / 400</gadget>
<output>1/400 = around 0.0025</output>

<gadget id="calculator">1 / 500</gadget>
<output>1/500 = around 0.002</output>

<gadget id="calculator">(1/400) - (1/500)</gadget>
<output>1/2_000 = around 0.0005</output>

<gadget id="calculator">1 / (1/2_000)</gadget>
<output>2_000</output>

<result>2_000</result>