A decimal, the decimal point is in the wrong position, 3.15 less than the original, what is the original decimal.
一个小数，小数点点错位置，比原来少3.15，原来这个小数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">3.15 / 9</gadget>
<output>0.35</output>

<gadget id="calculator">0.35 * 10</gadget>
<output>3.5</output>

<result>3.5</result>