On a map with a scale of (1/500000), the distance between A and B is 4 cm. What is the actual distance in kilometers between A and B?
在比例尺是(1/500000)的地图上，量得甲、乙两地相距4厘米，甲、乙两地之间的实际距离是多少千米？
<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">4 / (1/500_000) / 100_000</gadget>
<output>20</output>

<result>20</result>