After moving the decimal point of a decimal one place to the left, the obtained number is 3.87 smaller than the original number. What is the original number of this decimal?
把一个小数的小数点向左移动一位后，得到的数比原来的数小了3.87，这个小数原来是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">3.87 / 9</gadget>
<output>0.43</output>

<gadget id="calculator">0.43 * 10</gadget>
<output>4.3</output>

<result>4.3</result>