On the map of China with a scale of 1:2000000, the distance between A and B is 4 cm. Calculate, how many kilometers is the actual distance between A and B?
在比例尺是1：2000000的中国地图上，量得甲、乙的距离是4厘米．计算一下，甲、乙的实际距离大约是多少千米？
<gadget id="calculator">1 / 2_000_000</gadget>
<output>1/2_000_000 = around 0</output>

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

<result>80</result>