If the ratio of boys to girls in a class is 5:4, how much girls account for the whole class
某班男、女生人数的比是5：4，女生人数占全班的人数的多少
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<result>4/9 = around 0.444444</result>