The distance from Beijing to Tianjin is about 140km. On a map with a scale of 1:4,000,000, how many cm should be drawn.
北京到天津大约是140km，在比例尺是1：4000000的地图上，应画多少cm．
<gadget id="calculator">1 / 4_000_000</gadget>
<output>1/4_000_000 = around 0</output>

<gadget id="calculator">140 * 100_000 * (1/4_000_000)</gadget>
<output>7/2 = around 3.5</output>

<result>7/2 = around 3.5</result>