(2/5) of A number is 40, what is its (1/5)?
甲数的(2/5)是40，它的(1/5)是多少．
<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">40 / (2/5)</gadget>
<output>100</output>

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

<gadget id="calculator">100 * (1/5)</gadget>
<output>20</output>

<result>20</result>