In a book, the number of read pages is the number of unread pages (5/9), how much of the total number of unread pages
一本书，已看页数是未看页数的(5/9)，未看页数占全书的多少
<gadget id="calculator">5 + 9</gadget>
<output>14</output>

<gadget id="calculator">9 / 14</gadget>
<output>9/14 = around 0.642857</output>

<result>9/14 = around 0.642857</result>