On a 1:500,000 map, the length of Beijing Metro Line 1 is measured to be about 10cm. What is its actual length?
在一幅1：500000的地图上，量得北京一号地铁线长约是10cm，它的实际长度大约是多少？
<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">10 / (1/500_000) / 100_000</gadget>
<output>50</output>

<result>50</result>