(1/5) of a number is 30, what is 25% of this number.
一个数的(1/5)是30，这个数的25%是多少．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">30 / (1/5)</gadget>
<output>150</output>

<gadget id="calculator">25 / 100</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">150 * (1/4)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>