60% of a number is 18, what is 25% of this number?
一个数的60%是18，这个数的25%是多少．
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">18 / (3/5)</gadget>
<output>30</output>

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

<gadget id="calculator">30 * (1/4)</gadget>
<output>15/2 = around 7.5</output>

<result>15/2 = around 7.5</result>