20% of a number is 100, what is (3/5) of this number.
一个数的20%是100，这个数的(3/5)是多少．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">100 / (1/5)</gadget>
<output>500</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">500 * (3/5)</gadget>
<output>300</output>

<result>300</result>