On a map with a scale of 1:9000000, the distance from Nanjing to Beijing is 10 centimeters. How many kilometers is the actual distance from Nanjing to Beijing?
在比例尺是1：9000000的地图上，量得南京到北京的距离是10厘米．南京到北京的实际距离大约是多少千米？
<gadget id="calculator">1 / 9_000_000</gadget>
<output>1/9_000_000 = around 0</output>

<gadget id="calculator">10 / (1/9_000_000) / 100_000</gadget>
<output>900</output>

<result>900</result>