There are 30 girls in a class, and there are fewer boys than girls (1/5), how many boys are there?
某班有女生30人，男生比女生少(1/5)，男生有多少人？
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">30 * (4/5)</gadget>
<output>24</output>

<result>24</result>