In our school, there are five classes every five years. The ratio of boys to girls is 4:5. How many girls account for the total number of the class?
我们学校五年一班，男生与女生的比是4：5，女生占全班总数多少．
<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">5 / 9</gadget>
<output>5/9 = around 0.555556</output>

<result>5/9 = around 0.555556</result>