There are 20% more boys than girls in Class 61, how many girls account for the whole class
六1班男生比女生多二成，女生占全班人数的多少
<gadget id="calculator">2 / 10</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + 1 + (1/5)</gadget>
<output>11/5 = around 2.2</output>

<gadget id="calculator">1 / (11/5)</gadget>
<output>5/11 = around 0.454545</output>

<result>5/11 = around 0.454545</result>