Boys are 40 people, girls are 80% of boys, how many girls are there.
男生是40人，女生是男生的80%，女生多少人．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">40 * (4/5)</gadget>
<output>32</output>

<result>32</result>