The reduction in the number of boys (1/5) is equal to the number of girls, so how much less the number of girls is than the number of boys
男生人数减少(1/5)就等于女生人数，则女生人数比男生人数少多少
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>