If (1/4) of a number is equal to (3/5) of 30, what is the number?
一个数的(1/4)与30的(3/5)相等，那么这个数是多少．
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

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

<gadget id="calculator">(3/5) / (1/4)</gadget>
<output>12/5 = around 2.4</output>

<gadget id="calculator">30 * (12/5)</gadget>
<output>72</output>

<result>72</result>