The difference obtained by subtracting 4.5 from 125% of a number is 13.5. What is the number?
一个数的125%减去4.5所得的差是13.5，这个数是多少．
<gadget id="calculator">4.5 + 13.5</gadget>
<output>18</output>

<gadget id="calculator">125 / 100</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">18 / (5/4)</gadget>
<output>72/5 = around 14.4</output>

<result>72/5 = around 14.4</result>