A number, if its decimal part is expanded by 4 times, it is 3.4, and after being expanded by 7 times, it is 5.2. What is the decimal number?
一个数，如果把它的小数部分扩大4倍后是3.4，扩大7倍后是5.2，这个小数是多少．
<gadget id="calculator">5.2 - 3.4</gadget>
<output>1.8</output>

<gadget id="calculator">7 - 4</gadget>
<output>3</output>

<gadget id="calculator">1.8 / 3</gadget>
<output>0.6</output>

<gadget id="calculator">0.6 * 4</gadget>
<output>2.4</output>

<gadget id="calculator">3.4 - 2.4</gadget>
<output>1</output>

<gadget id="calculator">1 + 0.6</gadget>
<output>1.6</output>

<result>1.6</result>