my country has a population of 1.3 billion, and the ratio of my country's population to the world's population is 1:5. What is the population of the world?
我国有13亿人口，我国人口数量与世界人口数量的比是1：5．全世界人口数量是多少？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">13 / (1/5)</gadget>
<output>65</output>

<result>65</result>