There are 40 boys in a class, and there are fewer girls than boys (1/4). How many girls are there?
某班男生40人，女生比男生少(1/4)，女生多少人？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">40 * (3/4)</gadget>
<output>30</output>

<result>30</result>