For a one-digit decimal, if the decimal point is removed, the resulting number is 210.6 more than the original number. What is the original one-digit decimal?
一个一位小数，若去掉它的小数点，所得的数比原来多210.6，原来的一位小数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">210.6 / 9</gadget>
<output>23.4</output>

<result>23.4</result>