Move the decimal point of a decimal one place to the right, and the number obtained is 12.51 more than the original number. What is the original number?
把一个小数的小数点向右移动一位，得到的数比原数多12.51，原来的小数是多少？
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">12.51 / 9</gadget>
<output>1.39</output>

<result>1.39</result>