For a decimal, if the decimal point is moved one place to the right, the resulting number will increase by 31.86. What is this decimal?
一个小数，如果把小数点向右移动一位，所得的数比原来增加了31.86，这个小数是多少？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">31.86 / 9</gadget>
<output>3.54</output>

<result>3.54</result>