There are 30 male students and 20 female students in Class 5 and 6, how many female students account for the whole class
五6班有30名男同学，20名女同学，女同学占全班人数的多少
<gadget id="calculator">30 + 20</gadget>
<output>50</output>

<gadget id="calculator">20 / 50</gadget>
<output>2/5 = around 0.4</output>

<result>2/5 = around 0.4</result>