There are 50 students in Class 1, 40% of whom are girls. How many girls are there?
六一班有学生50人，女生占40%，女生有多少人．
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">50 * (2/5)</gadget>
<output>20</output>

<result>20</result>