The actual length is 30 kilometers, how many centimeters should be drawn on a 1:500000 map.
实际长度是30千米，画在1：500000的地图上，应画多少厘米．
<gadget id="calculator">1 / 500_000</gadget>
<output>1/500_000 = around 0.000002</output>

<gadget id="calculator">30 * 100_000 * (1/500_000)</gadget>
<output>6</output>

<result>6</result>