If the decimal point of a decimal is moved one place to the right and the original number is increased by 4.5, what is the original number?
如果把一个小数的小数点向右移动一位后比原数增加4.5，原数是多少．
<gadget id="calculator">10 - 1</gadget>
<output>9</output>

<gadget id="calculator">4.5 / 9</gadget>
<output>0.5</output>

<result>0.5</result>