An extra-curricular book, read it in a week, how much did you read this book in 3 days
一本课外书，一星期看完，3天看了这本书的多少
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">3 * (1/7)</gadget>
<output>3/7 = around 0.428571</output>

<result>3/7 = around 0.428571</result>