After the number of boys in the school is reduced by 20%, it is equal to the number of girls. What is the ratio of girls to boys in the school?
学校男生人数减少20%后与女生人数相等，学校中女生是男生的多少
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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

<result>4/5 = around 0.8</result>