The ratio of boys and girls in class 51 is 5:4, how many girls account for the whole class
五1班男、女生人数的比是5：4，女生占全班人数的多少
<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>