If you multiply the fractional part of a decimal by 4, the original decimal becomes 3.4; if you multiply it by 7, the original decimal becomes 5.2. What is this decimal?
如果把一个小数的小数部分乘4，原来的小数就成为3.4；如果乘7，原来的小数就成为5.2．原来这个小数是几？
<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>