For a number, if its decimal part is enlarged to 3 times, the number is 3.55. If its decimal part is enlarged to 8 times, the number is 7.8. What is the original number?
一个数，如果把它的小数部分扩大到原来的3倍，这个数是3.55，如果把它的小数部分扩大到原来的8倍，这个数是7.8，这个数原来是多少？
<gadget id="calculator">7.8 - 3.55</gadget>
<output>4.25</output>

<gadget id="calculator">8 - 3</gadget>
<output>5</output>

<gadget id="calculator">4.25 / 5</gadget>
<output>0.85</output>

<gadget id="calculator">0.85 * 3</gadget>
<output>2.55</output>

<gadget id="calculator">3.55 - 2.55</gadget>
<output>1</output>

<gadget id="calculator">1 + 0.85</gadget>
<output>1.85</output>

<result>1.85</result>