There are 1 fewer boys than girls (4/5), 19 boys, how many girls?
男生比女生的(4/5)少1人，男生19人，女生多少人？
<gadget id="calculator">19 + 1</gadget>
<output>20</output>

<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">20 / (4/5)</gadget>
<output>25</output>

<result>25</result>