After a number is expanded to 10 times the original number, it is 25.2 larger than the original number. What is the original number?
一个数扩大到原来的10倍后，比原数大25.2，原数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">25.2 / 9</gadget>
<output>2.8</output>

<result>2.8</result>