After the decimal point of a number is moved one place to the left, the resulting number is 4.86 smaller than the original one. What is the original number?
一个数的小数点向左移动一位后，得到的数比原来小4.86，原来的数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">4.86 / 9</gadget>
<output>0.54</output>

<gadget id="calculator">0.54 * 10</gadget>
<output>5.4</output>

<result>5.4</result>