There are 80 girls in the sixth grade, 20 fewer than boys, how much fewer girls than boys.
六年级有女生80人，比男生少20人，女生比男生少多少．
<gadget id="calculator">80 + 20</gadget>
<output>100</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

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