The scale of a map is 1:1000000, the distance on the map is 2.5 cm, how many kilometers is the actual distance?
一幅地图的比例尺是1：1000000，图上距离是2.5厘米，实际距离是多少千米．
<gadget id="calculator">1 / 1_000_000</gadget>
<output>1/1_000_000 = around 0.000001</output>

<gadget id="calculator">2.5 / (1/1_000_000) / 100_000</gadget>
<output>25</output>

<result>25</result>