The number of boys is 80% of the number of girls, and the number of girls is the number of boys.
男生人数是女生人数的80%，女生人数是男生人数的多少．
<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">1 / (4/5)</gadget>
<output>5/4 = around 1.25</output>

<result>5/4 = around 1.25</result>