If the decimal point of a number is moved one place to the right, it increases by 257.4 from the original number. What is the original number?
一个数的小数点向右移动一位后比原数增加了257.4，原数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">257.4 / 9</gadget>
<output>28.6</output>

<result>28.6</result>