The scale of a map is 1:500000, the actual distance is 150 kilometers, how many centimeters should be drawn on the map.
一副地图的比例尺是1：500000，实际距离是150千米在图上需要画多少厘米．
<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">150 * 100_000 * (1/500_000)</gadget>
<output>30</output>

<result>30</result>