In 2004, the population of Asia was about 3.9 billion, 400 million more than five times the total population of Europe. How many billion people is there in Europe?
2004年亚洲人口约39亿，比欧洲人口总数的5倍还多4亿人，欧洲人口大约有多少亿人？
<gadget id="calculator">39 - 4</gadget>
<output>35</output>

<gadget id="calculator">35 / 5</gadget>
<output>7</output>

<result>7</result>