30% of number A is 54, number B is 30% of 54, then number B is the number of A.
甲数的30%是54，乙数是54的30%，那么乙数是甲数的多少．
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">54 * (3/10)</gadget>
<output>81/5 = around 16.2</output>

<gadget id="calculator">54 / (3/10)</gadget>
<output>180</output>

<gadget id="calculator">(81/5) / 180</gadget>
<output>9/100 = around 0.09</output>

<result>9/100 = around 0.09</result>