There are 20 boys and 30 girls, how much more girls than boys.
男生20人，女生30人，女生比男生多多少．
<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<gadget id="calculator">10 / 20</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>