After multiplying a number by 10 times, it is 13.5 more than the original number, what is the original number?
把一个数扩大10倍后，比原来的数多13.5，原数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">13.5 / 9</gadget>
<output>1.5</output>

<result>1.5</result>