After the decimal point of a decimal is moved one place to the left, the resulting number is 3.78 smaller than the original number. Do you know what the original number is?
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3.78，你知道原来的数是多少吗？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">3.78 / 9</gadget>
<output>0.42</output>

<gadget id="calculator">0.42 * 10</gadget>
<output>4.2</output>

<result>4.2</result>