After adding, subtracting, and dividing a decimal number with itself, the sum of the sum, difference, and quotient is 10.8. What is the original number?
一个小数，与它自己相加、相减、相除后，和、差、商相加的和是10.8，原来这个数是多少．
<gadget id="calculator">10.8 - 0 - 1</gadget>
<output>9.8</output>

<gadget id="calculator">9.8 / 2</gadget>
<output>4.9</output>

<result>4.9</result>