A line segment of 2 cm on a map with a scale of 1:4000000 represents the actual distance in kilometers.
在比例尺是1：4000000的地图上2厘米的线段表示实际距离多少千米．
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">2 / (1/4_000_000) / 100_000</gadget>
<output>80</output>

<result>80</result>