After a decimal is enlarged by 10 times, it is 22.5 larger than the original number. What is the original number?
一个小数扩大10倍后，比原数大了22.5，这个原数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">22.5 / 9</gadget>
<output>2.5</output>

<result>2.5</result>