(4/5) of a number is 20, what is this number
一个数的(4/5)是20，这个数是多少
<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>